An Unoffical Deltarune TTRPG

GM’s Guide
DELTARUNE and UNDERTALE by Toby Fox.
Art taken from DELTARUNE and UNDERTALE.
Ruleset created by Icebrick1.
Version 2.5
 TABLE OF
INTRODUCTION - 3
CONTENTS
CRAFTING YOUR CAMPAIGN - 4
Advice on Structure - 4
SAVING and LOADING - 5
Making a Dark World - 6
CREATING ENEMIES - 9
Calculating Difficulty - 13
ITEMS - 14
EVOLVING MECHANICS - 18
Their Castle Town - 18
Status - 20
Elements - 26
Magic ITEMs - 29
Color Attacks - 29
Allies - 30
Quirks - 31
DISCLAIMER AND CONTACT - 33
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 INTRODUCTION
Welcome, welcome to the Game Master’s
Guide to DELTAROLL! Within these pages
you shall be granted the tools to
author your own game of DELTROLL.
These words are intended only for the
GM (Game Master), so if you’re a player
you should leave now - though if you do
read this book anyways (for example,
you’re considering about running
your own campaign of DELTAROLL while
being a player in another) this isn’t
going to ruin anything, it’ll just spoil
some surprises.
As GM, it’ll be your responsibility to
make the world for the players, play as
NPCs (Non-Player Characters),
adjudicate rules, and more. It can be a
demanding task at times, but the game
should be fun for you too, not just the
players, and we’ve done our best to
make it as easy as possible. When
you’re ready, read the next section
and go from there.

Beyond Deltarune
This document generally assumes you're running a campaign similar to DELTARUNE:
The characters live normal lives in the Light World, and have adventures in the
Dark World created by some kind of antagonist. However, it is fairly easy to adapt
the rules for other settings (such as a more UNDERTALE-like universe) - you
would essentially just run each location as a Dark World and ignore anything
related to the Light World. You can completely eschew elements like “Secret
Bosses” if you wish.

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 CRAFTING YOUR
CAMPAIGN
Advice on
Structure
Then, create what you need for solely
the next Chapter: enemies,
characters, ITEMs, etc. For this part,
you will need to use the rules to get
It’s very possible that if you sought these things mechanically robust.
out a Deltarune-themed game system, Once you’ve made just enough for what
you already have some ideas in mind is necessary, then play. Once you
for what you want to run. Maybe an AU complete that chapter, take a break
of Deltarune with familiar faces, a and make the next one, just going one
brand new story featuring Dark chapter at a time. Having some idea of
Worlds, or a speculative take on what what’s upcoming will allow you to set
Chapter 3 will be like. Ultimately, the things up in advance, while not
following are suggestions - there is no overwhelming you with a massive
“right” way to structure your quantity of work. Don’t let perfection
campaign, but we hope they shall be be the enemy of the good.
helpful anyways.
Create a rough outline of your whole
campaign. Don’t get too specific -
after all, plans rarely survive contact
with the players - just get a general
idea of areas you’d like to go,
characters you’d like to use, and
themes you’d like to explore. You don’t
need to use any of the rules for this
step, it’s just general concepts. Split
this up into “Chapters,” if you’re
cleaving close to the structure
DELTARUNE this should be pretty
obvious: every major Dark World is one
Chapter. If your structure is a little
stranger, just ensure each Chapter
has a climax with a big boss fight so
gaining an LV at the end feels earned.
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 For example, you might decide the first
SAVING and
LOADING
time players LOAD every Chapter are
free and have no negative effects.
Just be sure to communicate the
consequences of LOADING to the
The power to SAVE and LOAD is players so they aren’t blindsided
immensely powerful, and threatens to later when it does have negative
make players feel as if their actions, impacts.
and the outcome of battles, don’t
matter. If a plan goes wrong, why not The following is a suggested list of
LOAD and try something different, or effects of a 7 Chapter campaign:
even try the same thing and see if they
get lucky this time? 1-3: Purely cosmetic effects. The
environment is more cracked and worn.
For this reason, LOADING works quite a 4-6: Minor consequential effects. A
bit differently from how it is character’s parent loses their nice
presented in UNDERTALE/DELTARUNE. job; their family has moved somewhere
The effort of bringing an entire group more run-down; the main boss has a
of people back in time, memories intact, significantly meaner personality.
places a visible strain on the 7-12: Major impacts. A side character
universe, one that will tear it to pieces who was friendly now hates their guts.
if used too much. With every use of this An NPC is now on their deathbed.
power, the players find themselves in a Someone never existed.
slightly more deteriorated timeline. 13: Last chance. The world is clearly
The players should fear LOADING, crumbling. Some kind of massive tear
giving significance to their actions, has opened up in the sky which no
and their failures, while still allowing normal character can acknowledge.
the campaign to continue. 14: Failure. LOADING is no longer
possible. This may be the effective end
We suggest max LOADS be about twice of the campaign. Maybe some other
the number of Chapters you’ll have, a group of characters out there can
rather harsh limit. However, this is still SAVE this world however…
something you can definitely adjust to
your tastes.

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 Replaying Content
When possible, try not to force
Areas
DELTAROLL is divided into Chapters,
players to repeat content. For which are further divided into Areas,
example, if the players already won usually 3, each one taking one to two
a fight, then they are forced to four-hour sessions to cross. Each
LOAD before the fight, feel free to area typically has some general
come up with a way to skip the shared theme, like taking place in a
encounter, or just speed past it and desert, being music-focused, etc.
declare they got the same results Each one usually has 1-3 normal
as the first time. If you have the time encounters, and ends with a Mini-boss,
and ability, you could even come up except the final area which has a Main
with completely new content based Boss.
upon the deteriorating timeline to
replace what they did earlier. The Main Boss
The big bad of the Dark World. Their

Buff
Making a
Dark World
influence is felt throughout the entire
Dark World, making their defeat (or
redemption?) an appropriate climax
for the chapter. They are typically a
The following is an outline of Boss with LV equal to the Party.
everything a Dark World typically
contains. While it is recommended you Shops and ITEMs
take a look at this outline, we actually There’s usually at least 2 shops in a
recommend against following it given Dark World, one at the start so
religiously. Surprises and breaks from the players have access to equipment
the pattern give your campaign its early if they need it, and one at the
identity. Maybe this chapter has 7 end so the players can get stronger
short areas, rather than 3 medium ITEMs to prepare for the Main Boss and
sized ones. Maybe the “Main Boss” is Secret Boss.
actually friendly to the party. Maybe
the Secret Boss will take center stage Some free ITEMs should also be
and knock out the Main Boss! available - maybe they’re just given to
the party, or as rewards for beating
optional challenges or finding
something hidden. See the “ITEMs”
chapter for more advice.

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 Non-Combat
Encounters The Secret Boss
Not necessary by any means… but a
Non-Combat Encounters are problems beloved part of most Chapters. This is
that are best solved without using your chance to get weird and creepy,
combat. Of course, these also arise and for the players to feel a sense of
naturally without you putting them pride and accomplishment for finding
there, but it’s also a good idea to and overcoming a special optional
consciously put in challenges that challenge. The Boss’s presence should
can’t be solved with brute force. This be felt in the Chapter… but less
might take the form of an explicit directly than the Main Boss. Maybe a
puzzle, or just a general problem the shop NPC implies they have a dark past.
players will use their abilities and Maybe there’s a weird ominous locked
creativity to overcome. There is door in an area. Maybe some NPCs
usually at least one per Area. mention how a important figure in the
Dark World suddenly disappeared a
Examples: while ago.
* The players need to solve an
Buff explicitly given riddle or puzzle. There’s typically a little extra work
required to find the secret boss in the
* The players are locked in a cage. A first place. As a GM you should note
dim-witted guard outside holds the that many things that seem “obvious”
keys. to you are often much less obvious
than the players.
* The players need to cross a busy
freeway.
* The players need to cross a rushing
river.
* The players need special VIP access,
such as by stealing a VIP Card or
convincing someone to trade for it.
* The players need to sneak or fool a
guard that is impossible to beat in
combat by normal means.

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 You shouldn’t randomly require the
players to backtrack to an area they
Dark World Checklist
already cleared, or that they [ ] LW Opening Segment
interrogate an NPC unprompted about
their past. Give them multiple clues for [ ] The Main Boss
each step, such that if they want to
find the Secret Boss, they will, even if [ ] First Area
they might need a little extra help [ ] 1 - 3 enemy encounters
along the way. [ ] A non-combat encounter
[ ] At least 1 ITEM and/or Shop
The Secret Boss is a Boss with LV one [ ] A mini-boss
higher than the party, and is only
accessible after reaching the final [ ] Second Area
area. Failure is not unexpected, but if [ ] 1 - 3 enemy encounters
the players have a proper strategy, [ ] A non-combat encounter
they should succeed most of the time. [ ] At least 1 ITEM and/or Shop
For their efforts, the players are [ ] A mini-boss
a rewarded with more mysterious
[ ] Final Area
Buff information and powerful special ITEM [ ] 1-3 enemy encounters
that usually is 2 LV above the party.
[ ] A non-combat encounter
Falling into the Deep [ ] At least 1 ITEM and/or Shop
Many Dark Worlds take place on [ ] (Optional) Mini-Boss
cliffs with some kind of bottomless
void. Characters or objects that [ ] Main Boss Fight
fall into the deep fall until the start
of their turn, whereupon they take [ ]The Secret Boss Quest
2d6 damage from falling and
reappear prone somewhere near [ ] Secret Boss
the cliff’s edge.
[ ] LW Closing Segment

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 CREATING ENEMIES
Stats
For the most part, enemy stats work
Ranks
Enemies are split up into 4 ranks. For
very similarly to players. However, each one, a basic formula is provided
they have no MG stat, can gain no TP, for stats, but feel free to adjust up
and do not deal extra damage on a crit. and down a bit to make things
interesting. As stated elsewhere,
MM (Max Mercy) exceptions are often what makes
The enemy’s resolve to keep fighting. something interesting.
The amount of Mercy an enemy needs to
receive before they are Defeated. Enemies are formatted as follows:

HP Name LV 1 [Rank]
a [Element, if any]
The enemy’s durability. When an enemy MM [X], HP [X], DF [X], AT [X], SPD [X]
Buff runs out of HP, they are Defeated.
Enemy Description
DF Passive Feature: Description of
Defense. Attacks against enemies need passive feature.
to roll equal or above DF to hit.
Example Action - Description of
AT effects.
Attack power. Added to most attacks
and damage rolls. The specific action Example Attack (ATK) - [Type and
will tell you when to add it. Range] - On hit: [Damage and effect]
SP Just like player characters, enemies
Speed. They can move this distance for can also take the standard actions
free on each of their turns. like MOVE, DEFEND (for no TP) and FLEE;
though they cannot ACT or CHECK.

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 Mooks Elite
Mooks are weak enemies that are only Elites are slightly harder normal
dangerous in swarms. They should take enemies. They are about 2x as strong
about 2 actions to defeat and take as mooks, taking 4 actions to defeat
many actions to defeat the players. and only needing 4 actions to take
down a player.
Basic Formula:
MM: 12 + LV Basic Formula:
HP: 5 + 2*LV MM: 24 + 2*LV
DF: 7 + LV/2 HP: 10 + 4*LV
AT: 1 + LV DF: 7 + LV/2
Damage: 1d8 + AT AT: 2 + LV
Damage: 1d10 + AT
Example:
Rudinn LV 2 Mook Example:
Earth/Blade Rudinn Ranger LV 2 Elite
a
MM 14, HP 10, DF 8, AT 2, SP 6 Earth/Blade
Buff
MM 25, HP 15, DF 9, AT 4, SP 6
Diamond Cutter (ATK) – ranged, 12 sq. –
On hit: 1d8 + AT damage. Red Cutter (ATK) – ranged, 12 sq. – On
hit: 1d8 + AT damage, target is pushed 3
Diamond Short Sword (ATK) – melee, 1 squares in any direction.
sq. – On hit: 1d6 + AT damage, the target
is pushed back one square. Red Short Sword (ATK) – melee, 1 sq. –
On hit: 1d6 + AT damage, the target is
Diamond Release - Mark up to 9 pushed back one square and knocked
squares with diamonds. At the start of prone.
the Rudinn’s next turn, any character
in a marked square takes 2d6 + AT Red Diamonds: Mark up to 9 squares
damage and the marked squares with diamonds. At the start of the
disappear. Rudinn Ranger’s next turn, any
character in a marked square takes
2d6 + AT damage. These marked
squares only disappear when Rudinn
Ranger is defeated.
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 Capture: K. Round hops up to 6 squares
Mini-Boss diagonally and makes an attack for 1d8
+ AT damage on anyone they pass over.
Mini-boss are notable enemies that will
be harder to defeat. They are often If K. Round passed over any enemies,
fought alongside some lesser enemies. they can take this action again for
They should take about 10 actions to free. However, K. Round cannot jump
beat and can down a player in 2 turns. over the same target twice in one
They can usually take 2 actions every round.
turn. (Most likely, it will take more than
10 actions as the players are forced Kick (ATK) – melee, 2 sq. – On hit: 1d6 +
to spend turns on defensive actions.) AT damage, target is knocked prone.

Basic Formula: Star Kick (ATK) – area, 6 square long

MM: 80 + 5*LV line – On hit: 1d4 + AT damage. On miss:
HP: 50 + 10*LV Still deal half damage.
DF: 7 + LV/2
AT: 2 + LV
a
Damage: 1d10 + AT, twice per turn.
Buff
K. Round LV 2 Mini-Boss
Ice/Order
MM 100, HP 50, DF 8, AT 4, SP 8
Mini-Boss: K. Round takes up a 2x2
space. K. Round takes two actions
every turn. They cannot both be the
same action.

Self-Care - Fully restore all HP and

gain +1 AT. Will only do this once, and
only if below 50% HP.

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 Spade Toss (ATK) – Ranged, 24 sq. – On
Boss hit: 1d6 + AT damage.
Bosses are the climax of an entire arc.
They should be difficult and feel Chain of Justice (ATK) – Melee, 12 sq. –
special. They can take 2 actions every On hit: 1d4 + AT damage. The target is
turn and have unique mechanics. They “Restrained,” which reduces their SP
should take about 14 actions to beat to 0. The Restrained status is ended if
and can down a player in 2 turns, the target is somehow moved, or if King
sometimes 1 turn if they get lucky. is moved more than 12 sq. away.
Basic Formula: Chain Walls: Walls of razor-sharp
MM: 130 + 10*LV chains fill 24 squares of the
HP: 60 + 15*LV battlefield. The first time each turn a
DF: 8 + LV/2 given character enters a square of
AT: 4 + LV chains they take 2d6 damage (don’t
Damage: 1d10 + AT, twice per turn. add AT). King can dismiss the Chains on
a his turn, but he must dismiss all the
King LV 1 Boss Chains at once.
Buff
Fire/Chaos
MM 120, HP 75, DF 8, AT 5, SP 6 Jaw Reel: Cannot be taken on the same
turn as Chain of Justice. King reels in a
Boss: King takes up a 2x2 space. King target he has Restrained, moving them
can take two actions every turn. a square adjacent to King (making them
no longer Restrained.) King then makes
Cruel: Unless it’s especially the following attack: melee, 1 sq. – On
exceptional, all ACTS against King are hit: 2d10 + AT damage.
at best Weak.
Tyrannize: King can only use this
Tired: At above 60 Mercy or below 35 ability once per battle and only when
HP, King’s AT and DF are reduced by 1. If he has above 60 Mercy or below 35 HP.
he is both, then reduce them by a He takes control of a player within 12
further 1. squares with an imposing command. King
controls their movement and action,
Spade Swing (ATK) – Melee, 2 sq. – On which are taken immediately. On that
hit: 1d8 + AT damage, shove the target player’s next turn, they do not move
up to 2 squares. and can take no action.
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 Encounter Difficulty

Calculating
Difficulty
Power
12 below party Trivial
or less
8 below party Easy
Using the Party’s LV, you can calculate
the approximate difficulty of an 4 below party Moderate
encounter and amount of D$ it awards. Equal to party Challenging
To do this, you need to calculate the
party’s “Total Power.” The player’s 4 above party Very Challenging
Total Power is: 8 above party Almost Impossible
or more
Number of players * (4 + average LV +
1/5 the encounters won by violence). ACT Effectiveness
As GM you’ll need to strike a balance
For example, a party of four LV 1 between encouraging creativity
a players would have a Total Power of 4 * with ACTs and setting the game
Buff (4 + 1) = 20. speed.
A party of four LV 3 players, with 10
encounters won by violence, would If you make it so that nothing but
have 4 * (4 + 3 + 2) = 36 Power. perfect ACTs work well, you might
run into a slog as the players spend
The enemy’s Total Power of based on a long time deciding on this perfect
the enemies Rank and LV: ACT or just slowly whittle the enemy
Mook: 1 + LV/2 down with weak ACTs.
Elite: 2 + LV
Mini-Boss: 6 + 3*LV Meanwhile, if you make every ACT
Boss: 16 + 4*LV Critically Effective, players might
stop considering their actions and
Ex. A LV 2 Boss would have 16 + 4*2 = 24 fights will end very fast.
total Power.
We recommend making most ACTs
An encounter generally rewards half Moderate, even kind of bad ones,
but to be slightly picky with Very
its Power as D$. Strong and very picky with what
counts as Critically Effective ACTs.
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 ITEMS
Similar to enemies, ITEMs have their LV one above the player’s should be a
own LV hidden from players, and there little harder, requiring work to find or
is a basic formula ITEMs should roughly coming from a shop late in the Chapter.
follow based on their LV: LV two above the players is a rare
event, usually reserved for beating
Weapon: 4 + LV + AT damage, 10 + 5*LV D$ the secret boss. The Basic ITEMs found
in the Player’s Handbook are LV 1.
Armor: 2+LV DF, 10 + 5*LV D$ ITEMs generally sell for half their
normal price.
Consumable (Cheap): Restore 8 + LV HP,
4 + 2*LV D$ Weapons should generally be useful
for attacks, not ACTING, so weapons
Consumable (Fancy): Restore 14 + 2*LV boosting DF should be used with
HP, 8 + 4*LV D$ caution. DELTAROLL is designed so
a parties can deftly switch between
BuffThese formulas are only for the most using Mercy or Violence. If the party
basic of ITEMs, to create more complex specializes too hard in Mercy, like by
and interesting ITEMs, you sacrifice them all using ACTING focused Weapons,
some amount of damage/DF/Healing for this is lost.
an interesting ability (or suffer some
drawback, such as reduced SP, in For armor, generally, +1 to another
exchange for further benefits.) stat such as SP, MG, or AT is worth
losing 1 DF. So for example, LV 5 armor
Generally, ITEMs with LV equal to the normally gives +7 DF, so LV 5 Magic
players should be easy to find, being Robes might give +5 DF, +2 MG. However,
found for free and sold at shops early these bonuses to other stats
in the Chapter. shouldn’t be more than +5.

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 Sample Weapons
(You can simply ignore the damage type if you aren’t using the Elements rules.)
Name LV D$ Range Description
Spooky 2 14 Melee On hit: d8 + AT Earth/Blade damage. On crit: Terrify the
Sword target, on the next turn, they cannot willingly move closer to
you.
Plastic 2 18 Melee, 2 On hit: d10 + AT Ice/Order damage.
Halberd sq.
Devilsknife 3 28 Melee Offensive SPELLS cost 5 less TP to use (to a minimum of 1 TP).
On hit: 1d10 + AT Fire/Chaos damage.
Adamant 4 32 Melee You cannot move and attack on the same turn. On hit: 2d10 +
Maul 2*AT Ice/Order damage.
Sniper Ranged, +3 CRIT (Increases your crit range by 3. Meaning by default,
5 34 you crit on a 17 or higher). On hit: 2d6 + AT Earth/Blade
Crossbow 24 sq. damage.
a
BuffWire Whip 6 39 Melee, 3 On hit: 2d8 + AT Elec/Holy damage, pull the target up to 3
sq. squares directly towards you.
Mayhem 7 42 Melee On hit: 1d20 + AT Fire/Chaos damage, the target can either
move or take an action on their next turn, not both. On miss:
Flail Hit yourself. Idiot.
Gargantua 8 48 Melee When you attack with this weapon, lose your action next turn.
On hit: 3d12 + 2*AT Earth/Blade damage, push the target 3
Mace squares in any direction.
Fusion 9 56 Ranged, On hit: 3d6 + AT Elec/Holy damage, you can choose to swap
Rifle 12 sq. positions between you and the target, teleporting.
Drain 10 62 Melee On hit: 2d10 + AT Ice/Order damage, heal HP equal to half the
Talons damage inflicted.
Spiral 11 64 Melee, 2 On hit: 4d6 + AT Earth/Blade damage, place the target within
Spear sq. an occupied square in range.
Twisted 12 73 Melee When you take damage, gain 1 AT, to a max of 5 AT. Lose this
bonus at the end of battle. On hit: 3d10 + AT Earth/Blade
Sword damage.
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 Sample Armor
It is fairly easy to adjust armor LV by changing the DF by an equal amount. For
example, LV 2 Sacrosanct Raiments would give 10 - 7 = +3 DF instead.
Name LV D$ DF Description
Lightning 2 14 +3 +1 SP.
Belt
Devilstail 3 28 +2 +2 AT, +2 MG.
Thick 4 31 +3 Reduce all damage taken by 2 (TP gain is also reduced).
Sweater
Blurred Cape 5 35 +5 +4 additional DF against ranged attacks.
Super 6 40 +7 When you CHECK, gain 1d10 TP.
Scouter
Fine Robes 7 46 +6 +3 MG.
a
BuffCotton Boots 8 48 +9 Immune to damage from falling.

Sacrosanct 9 54 +10 You can spend 10 TP when you use an ITEM to use it on a
Raiments character up to 12 squares away.
Altruist When an ally takes damage within 3 squares, you can choose to
10 60 +10 take the damage instead. This damage can’t be reduced by any
Plate means.
Shadow 11 65 +11 Whenever you take damage, teleport 3 squares to an
Mantle unoccupied square of your choice.
Twisted 12 73 +10 You can take two actions per turn. At the end of your turn,
Crown lose 6 HP (this gives TP).

( 16 )
 Sample Consumables
Name LV D$ Effect
Jet Coffee 1 6 Restore 6 HP, double SP until the end of your next turn.
Thick Moss 2 10 Restore 22 HP. You cannot use this ITEM and move on the same
turn.
Explosive Can be tossed up to 6 squares, exploding in a 3x3 square. Make
Potion 2 8 an attack that deals 2d6 + AT Fire/Chaos damage on hit, or half
on a miss.
Spicy Pepper 3 8 Lose 1 HP, gain +1 AT until the end of battle. Doesn’t stack.
Tension Bit 4 16 Gain 25 TP.
Spincake 5 26 Restore 8 HP to up to 3 allies within 12 squares of you.
Regenerating Restore 5 HP, gain 5 Regen. (You heal HP equal to Regen at the
a Moss 6 26 end of your turn. Regen does not stack. Lose all Regen when
Buff reduced to 0 HP, or at the end of battle.)
Revive Mint 7 30 Can only be used on someone below 0 HP. Sets their HP to half
their Max HP.
Glitch Cream 8 20 Restore 14 HP. Teleport up to 12 squares to an occupied square.
Bubble Tea 9 24 Restore
your SP.
20 HP. Until the end of your turn, you can fly at double

Murk Wisp 10 34 Restore 4 HP. Gain 1 Void. (When you would take damage, negate it
and lose 1 Void.)
Shadow Feast 11 36 Gain 100 TP, heal to Max HP. Lose 5 Max HP permanently.

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 EVOLVING
MECHANICS
The mechanics presented in the Typically, the town begins with
Player’s Handbook were as simplified sufficient housing for all the
as possible while still capturing the darkners, rooms for all the player
essence of DELTARUNE. The following characters, a store from the previous
are a set of optional rules that will dark world, a dungeon for darkners
enhance the experience. We suggest too dangerous to release, and the
introducing about 1-2 per Chapter, following building:
gradually increasing the complexity of
the game as the players get used to Forge - Once per visit, fuse two ITEMs
the rules. into a new form for 5*LV D$.
Additionally, once per visit the
a
Buff Their Castle
Town
players can pay 10 + 5*LV D$ can
upgrade an ITEM below their LV to
match their current LV. ITEMs that are
already equal to or higher than the
player’s LV cannot be upgraded.
Generally, darkners can only exist in
their original fountain, but the Grand (This is an opportunity for you to make
Fountain is an exception. Its pure up a new ITEM based on what the
darkness allows any darkner to exist players want. If you can’t think of
there. It is built by the hopes and something on the spot, feel free to let
dreams of those that reside within it. the players keep the ITEMs until the
next session when you figure out the
Every chapter, the players usually fusion. Generally, Secret Boss ITEMs
visit their Castle Town twice: once at cannot be fused.)
the start, before the main events of
the chapter, and once at the end, right
before ending the chapter. Similarly,
they can choose one building to add to
their town every visit, with it being
complete the next time they come.
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 Alchemy Lab - Provides special
Sample Buildings potions, elixirs, and bombs which have
The following are some suggestions both offensive and healing utility.
for what they might build. First is the (Players have limited materials to
description you would give the craft ITEMs. Usually, they can make
players, parenthesis are the rules either 2 cheap Consumable ITEMs per
for the GM. Unless stated otherwise, visit, or 1 fancy Consumable ITEM.)
assume ITEMs provided are equal to Observatory - Study the fabric of the
party LV. Dark World. Provides insight into your
next adventure and gives you useful
Garden - Get a collection of potent tips and information, such as what
plant-based ITEMs, completely free, elements you should prepare for.
every visit. (Give the players helpful information
(1 cheap and 1 fancy consumable ITEM such as: elements they should
per visit. You might consider letting prepare, a clue towards the Secret
the players choose what to grow.) Boss, a hint for a puzzle, etc.)
Cafe - Buy powerful drink-themed Cafe Training Grounds - Allow the Fortress
a ITEMs from this special store. Updates
Buff every chapter. Also provides you with Villagers to practice fighting and
battles. Bring one Darkner a chapter
a bit of income and a place to hang out. to help out in some way.
(An extra store that sells consumable (Once per chapter, the players can
ITEMs 1 LV higher than the party. Also deploy a Mook or Elite rank enemy from
gives the party 5 + LV D$ every visit.) a past chapter to assist them. After
Meditation Chamber - Strengthen body the scene, they quickly turn to stone.
and mind with a bit of rest. Gives the They get better once brought back to
entire party buffs that last until the the Grand Fountain.)
next chapter. Communication Array - Establish the
(Players choose one of: +1 AT, +1 DF, +1 Dark World communication system.
MG, +5 max HP, +2 SP, +1 to a Skill. You Provides the party with Dark Phones
might other buffs, such as immunity to so they can always be in contact with
attack of opportunity, resistance to each other, and future Dark Worlds will
particular element, etc.) have phone booths that connect to the
Blacksmith Hyperforge - The Castle Town.
Blacksmith can now fuse up to 2 times (Self-explanatory. Phone Booths might
per visit and can upgrade an ITEM twice be helpful to get advice or clues.)
per chapter!
( 19 )
 Bardic College - Practice your ACTing Arena - Face a true challenge at the
skills and get an extra Style for your arena. You only get one try, and if you
ACTs for the next chapter. Even pass, gain a permanent minor buff!
monsters can learn these tricks! ITEMs you use for this fight are
(All player characters, including refunded at the end.
MONSTERs, learn a Style they can use (Once per Chapter, the players can
with their ACTs. They can change what challenge the arena, a battle of Almost
Style this is whenever they visit the Impossible difficulty with a medley of
town.) past enemies. Should they succeed,
Wizard Tower - Practice Magic, learn everyone in the party gets +2 max HP.
an extra SPELL or improve an existing If this fight is failed, LOADING doesn’t
SPELL for the next chapter. Even allow you to retry. The Arena is more
humans can learn to use Magic ITEMs! about wanting a hard fight than
(All MONSTERs learn an additional getting stronger.)
SPELL, or learn a new Style for a Spell.

a
They can change the SPELL/Style
every visit. In addition, it functions as
Buff a shop that sells Magic ITEMs.)
Status
Tavern - The home of adventure. Sleep Statuses is already used in the main
to recover HP above your maximum and rules a little, but this document
listen to rumors to discover an extra expands them massively. It’s often fun
quest which gives special rewards to base enemies on inflicting a
once per visit. particular status onto the party, and
(Players gain +5 HP above their they can be used for ideas for ITEMs
maximum. Once this HP is lost, it cannot and SPELLs. However, you should try
be recovered except by sleeping at not to put too many in a single fight,
the tavern again. The Quest is an since it can get overwhelming to track.
optional challenge the players can
undertake for a reward. For example, Note that for removing Statuses a
they might be tasked with stealing a character doesn’t need to DEFEND
special hammer in the Light World, themselves, it’s also possible DEFEND
which turns into a legendary smith an adjacent ally.
that can upgrade ITEMs to above the
party’s LV.)

( 20 )
 Radiance
Status Descriptions At the end of your turn, all targets of
“X” is used a stand-in for how many your choice within X squares
stacks of that Status you have. For (including yourself) regain 1d6 HP.
example, if you have Regen 5, you Lose 2 Radiance at the end of your
regain 5 HP at the end of our turn. turn.

Note the differences in how statuses Reach

end: some end on their own, others Increase the range of all your attacks
require you to DEFEND, etc. by X. Lasts until the end of battle.
Beneficial Regen
Bounce Regain X HP at the end of your turn.
Increase SP by X. You can jump at full Doesn’t stack: when you would gain
SP, rather than half. Whenever you Regen, it overwrites existing Regen.
take damage, you can move X squares Lose all Regen at the end of battle or
a in a direction of your choice without when you reach 0 HP.
Buff provoking opportunity attacks. Lose 1
Bounce when you take damage. Resolve
When you would gain Mercy, reduce it
Dodge by X. Whenever you take damage, lose
Increase SP and DF by X. Lose 1 Dodge an equal amount of Resolve.
at the end of your turn.
Root
Might Regain X HP and lose X Mercy at the
Add +X to your AT, DF, MG, and Mercy start of your turn. When moved
rolls. All Might is lost at the start of (whether willingly or not) lose all Root.
your turn. Also lose all Root when you hit 0 HP.

Pierce Sacrifice
The target of your next attack loses X When you see an ally within 12 squares
HP, then reduce Pierce by 1. This you take damage, you can spend
happens whether you hit or miss and Sacrifice to take the damage instead.
ignores all damage reduction. The amount of damage you can redirect
is equal to Sacrifice spent.

( 21 )
 Sanctity Vigor
When you would gain a harmful Status, Increase the damage of the next
reduce Sanctity by 1 and don’t gain the successful attack by X, then lose all
harmful status. Vigor.
Shadow Void
When an attack would hit you, roll a d10. When you would take damage, negate it
If it’s less than your Shadow, the (gain no TP) and lose 1 Void.
attack misses. CHECK reduces your
Shadow by 1, but has no other effect. Harmful
Blind
Slippery You cannot see. Take -4 to attack
Increase SP by X. You do not provoke rolls, attacks against you gain +4 to
attacks of opportunity. Lose 1 hit. Lose 1 Blind at the end of your turn
Slippery when you take damage. and when DEFENDed.

Spines Burn
a Increase SP by X. At the end of your
Buff When hit by an attack, deal X damage to turn take X damage and reduce Burn by
the attacker. Reduce Spines by 1 at the
start of your turn and when you take 1. You are required to move at least 1
damage. square every turn if you are able.
Remove all Burn when DEFENDed or when
Trance you hit 0 HP.
Reduce the cost of all TP effects by X,
to a minimum of 1. At the end of your Decay
turn, reduce Trance by 1. At the end of your turn, lose X HP and
increase decay by 1. Lose all Decay
Transient when you reach 0 HP.
Ignore orange, blue, and hindering
terrain. At the end of your turn, Dissolution
reduce Transient by 1. Increase all damage taken by X. Remove
1 Dissolution when DEFENDed.

( 22 )
 Frost Sleep
Reduce SP by X. Lose 1 Frost at the end When Sleep is equal to or greater than
of your turn and when DEFENDed. current HP, fall unconscious.
Whenever you take damage, lose an
Glitch equal amount of Sleep.
At the end of movement, teleport X
squares in a random direction. Lose all Slow
Glitch if you don’t move for a turn. Reduce SP by X. All Slow is lost at the
end of your turn.
Leak
Lose X HP at the end of your turn. When Taunt
you receive healing, reduce Leak by Damage is reduced by X except against
the same amount. Lose all Leak when the target that gave you Taunt.
you hit 0 hp. Reduce by 1 whenever affected by a
foe other than the taunter. Lose all
Mute Taunt when DEFENDed.
a You can’t gain TP for the party,
Buff including from DEFENDing or from Vulnerability
attacks targeting you. Reduce by 1 at The next time you take damage,
the start of your turn. increase it by X and remove all
Vulnerability Lose all Vulnerability
Paralysis when DEFENDed.
When Paralysis is greater than
current HP, you can take no actions Weakness
and cannot move. Lose all Paralysis Reduce AT and DF by X. Lose all
when DEFENDed. Weakness at the start of your turn.

Poison StatusStyles
SPELLS and
At the end of your turn, lose 10% of
your HP and reduce Poison by 1. Lose These are additional SPELLS and
all Poison when you reach 0 HP. Styles the players can learn upon
gaining LV. It is up to you whether you
Silence want to release them all, or pick and
You can’t use any ability that requires choose. You might even want to lock
TP. Lose 1 Silence at the start of your them behind a special quest or similar.
turn and when DEFENDed.
( 23 )
 Offensive SPELLS Buffing SPELLS
MAGIC STRIKE (0 TP) RADIANT AURA (75 TP)
As an action, make an attack, as if As an action, grant yourself Radiance
using the FIGHT action. Not very useful equal to MG.
on its own but, Styles you apply to this
spell apply to the attack, such as CLEANSE (50 TP)
Status-Infused below. As an action, decrease the Statuses
on yourself or an adjacent target by
ENVENOM (20*X TP) MG. (Example: You have 3 MG, the target
As an action, inflict a target within 12 has Burn 3, and Poison 2. You can
squares X Poison, up to your MG. Costs completely remove the Burn, or choose
20 TP per Poison applied. Choose the to remove the Poison and only 1 of the
amount before casting this. Burn.) Note this can be used
offensively to remove positive
ROT (22 - MG TP) Statuses.
As an action, inflict a target within 12
a
squares 1 Decay. This costs 22 TP, PURE AURA (20 TP)
Buff
minus your MG. As an action, grant yourself or a
target within 12 squares Sanctity
CREATE OPENING (11 TP) equal to MG.
As an action, inflict a target within 12
squares Vulnerability equal to double ACCELERATE (35 TP)
your MG. As an action, grant yourself or a
target within 12 squares Dodge equal
INCINERATE (12 TP) to MG.
As an action, inflict a target within 12
squares Burn equal to MG. EXTEND (10 TP)
As an action, grant yourself 1 Reach.
DISSOLVE (20 - MG TP) The maximum Reach you can have from
As an action, inflict a target within 12 this SPELL is equal to your MG.
squares 1 Dissolution. This costs 20
TP, minus your MG. SHARPEN (9 TP)
As an action, grant yourself or a
target within 12 squares Pierce equal
to MG.
( 24 )
THORN SHIELD (8 TP)
As an action, grant yourself or a target within 12 squares Spines equal to MG.
ETHEREALNESS (30 TP)
No action required, grant yourself or a target within 12 squares Transient equal to
MG.
Styles
Status-Infused (+5 TP) - Choose a Status SPELL
(it does not have to be one you know) when you
take this Style. Inflict the effects of that SPELL
on yourself or a target. This costs 5 more TP than
the SPELL.

HUMANS can use this, but note they have 0 MG by

default.

Exposing (-10 TP) - Gain 2 Dissolution.

Status Weapons
Name LV D$ Range Description
On hit: d8 + AT Earth/Blade damage, inflict 1
Serrated Sickle 3 25 Melee Leak.
Alchemist’s
Crossbow 4 30 Ranged, 12 sq. On hit: d6 + AT damage, inflict 2 Poison.
You always have 1 Pierce. On hit: 2d6 + AT
Ghost Dagger 5 37 Melee damage.
On hit: 3d4 + AT Earth/Blade damage, apply 1
Dissolution to the target. (Increase damage
Serrated Knife 6 42 Melee Dissolution. The target removes 1
Dissolution they DEFEND.)
Combat On hit: 2d6 + AT Elec/Holy damage. On crit:
Aspergillum 7 44 Melee Gain 2 Radiance.

( 25 )
 Status Armors
Name LV D$ DF Description
As long as you are wearing this armor, you always have
Softened Armor 2 14 +7 Muted 1.
Spiked Shield 3 20 +3 At the start of battle, gain Spines 4.
Status Consumables
Name LV D$ Description
Emergency Rations 2 8 Restore 22 HP. Gain 1 Decay.
Make a ranged attack against a target within 12
Poison Dart 3 10 squares. On hit: Inflict 1 Poison.
Invigorating
Draught 4 20 Restore 8 HP, gain 6 Vigor.
Silver Water 5 28 Restore 5 HP. Remove all negative Statuses.
Fertilizer 6 16 Restore 6 HP. Gain 6 Root.
Clarifying Drink 7 36 Restore 5 HP. Gain 8 Trance.

Elements
There are 4 main elements: Earth/
Defender -> Elec/ Earth/ Ice/ Fire/
Attacker v Holy Blade Order Chaos
Blade, Fire/Chaos, Ice/Order, and Elec/Holy 1/2 1x 1x 1.5x
Elec/Holy; and “Other” as a catch-all
for everything else. Other includes
many of the elements from Deltarune Earth/Blade 1.5x 1/2 1x 1x
that are too specific to use often,
such as Puzzle and Cat. Every enemy
has an element, and takes half damage Ice/Order 1x 1.5x 1/2 1x
from their own element, but one and a
half times damage from another
element. The relationship is as follows: Fire/Chaos 1x 1x 1.5x 1/2

( 26 )
For example, an Elec/Holy attack does Elemental Status
half damage against Elec/Holy enemies, Elemental Resistance
but does 1.5x damage against Fire/ Take half damage from one element,
Chaos enemies. specified from the source of this
status. Lose 1 Elemental Resistance
Weapons all have their own elemental when you take damage from that
damage they inflict. The players element.
choose what element their SPELLs are
when this mechanic is introduced. If Elemental Vulnerability
they wish, they can choose an element Take 1.5x damage from a one element,
that falls under “Other” to specified from the source of this
effectively opt out of the Element status. Lose 1 Elemental Vulnerability
system. when you take damage from that
element, and when DEFENDed.
If you want, you can introduce new
elements, maybe just for a Chapter,
without any particular issue. Ex. For a
Elemental SPELL
ELEMENT SHIELD (25 TP)
mouse themed chapter, you might Choose one element when you gain this
introduce the Mouse/Dust element, SPELL. As an action, give yourself or
and decide it is weak to the Puppet/Cat an ally within 12 squares Elemental
element. Players can choose to buy Resistance of the chosen element
armor to resist Mouse/Dust, or equal to your MG.
Puppet/Cat weapons to deal with mouse
enemies. Elemental Style
Elemental ITEMs Alternate Element (+14 TP) - Apply this
Sky Mantle - LV 5 Armor - +5 DF, take to a SPELL that inflicts damage. Choose
half damage from Elec/Holy. any element. The SPELL deals that
element instead of its normal element.
Ice Pop - LV 3 Consumable - Gain You can choose a different element
Elemental Resistance 3 against Ice/ every time you use this.
Order.
Universal Sword - LV 4 Weapon - As an
action, you can change what element
this weapon inflicts. On hit: Deal 1d10 +
AT damage.
( 27 )
 Trinkets
Trinkets are ITEMs similar to armor, providing a small passive benefit as long as they
are worn. They can be worn alongside armor, though you can only wear one Trinket at
a time.
Trinket: +LV/3 DF, 5*LV D$.
Name LV D$ Effect
No action required, you can lose any amount of HP to
Red Drop Amulet 2 10 gain an equal amount of TP. This works outside battle.
(though note all TP is lost when combat begins).
Big Monocle 3 15 +3 AT when making attacks of opportunity.
Rainbow Earring 4 20 +1 DF. As an action, you can change this bonus to +1 AT, +1
MG, or +1 SP instead.
Cool Necktie 5 25 +2 CRIT. (Increase your crit range by 2. Meaning by
default, you would crit on a roll of 17-20.)
Spring Brace 6 30 You can forgo your movement on a turn to increase the
reach of your attacks by 6.
Malleable Stone 7 35 Whenever you gain TP from an attack hitting you,
increase the TP gained by 8.
Tension Charm 8 40 At the start of combat, gain 25 TP.
Commander’s Banner 9 45 Once per turn, you can move a willing character 6
squares directly towards you.
Whenever you take damage from an attack, reduce it by
Bounce Ball 10 50 2 and you can choose to move up to 3 squares directly
away from the source of the attack.
Snow Globe 11 55 As an action, give yourself or an adjacent character 6 +
1d6 Trance.
If you have 0 Void, you can, as an action, lose 5 HP (gain
Void Bubble 12 60 TP for this) and gain 1 Void. Lose this Void if you remove
this ITEM.
( 28 )
Magic Items Color
Attacks
Magic ITEMs are a special class of
ITEMs that use TP to cause an effect. This ruleset adds another tactical
They are infinitely reusable, so long element to combat by introducing
as you have TP. Even HUMANs can use orange and blue squares and attacks.
Magic Items, though since many scale
off MG, they aren’t necessarily good Some attacks or abilities can create
at using all of them. orange or blue squares. If you end
your turn in an orange square, you
Magic ITEMs generally cost 20 + 3*LV take the effects listed in the thing
D$. Their effects should be about that created it. If you exit a blue
equivalent to a SPELL, but at the cost square, you trigger those effects.
of 10 more TP, minus the LV of the ITEM. Orange and blue squares are
For example, a LV 5 Magic ITEM might destroyed if they are dealt any
recreate the effects of DISAPPEAR at damage (attacks automatically hit
the cost of (29 + 10 - 5) = 34 TP. against them). Unless stated
otherwise, orange and blue squares
An easy way to make Magic ITEMs a little disappear at the start of the
more interesting is to slightly vary creator’s next turn.
how they work. For example, perhaps
this version of DISAPPEAR also creates Blue attacks can only hit targets that
a 3x3 cloud of smoke that blinds those moved last turn. Orange attacks can
inside it. only hit targets that didn’t move.
Some interesting strategies you might
employ:
* An enemy with a very powerful orange
attack that has weak minions to hold
you in place.
* A slow moving melee enemy creates
fields of blue squares.
* Enemies that gradually slow you down
on hit, and create fields of orange
squares.
( 29 )
 Spells
ORANGE SPREAD (18 TP)
Allies
Through their journeys, the party may
Cover a 6x6 square area in orange acquire NPC allies who travel with them.
squares. Characters that end their This might include Darkner companions
turn in an orange square take 1d6 + MG (similar to Ralsei from DELTARUNE), or
damage. All orange squares disappear fellow Lightners. Simply create them
at the start of your next turn. Styles using the same rules as player
that affect a target only trigger when characters (treat Darkners as
they take damage from this SPELL. MONSTERs), with the following changes:

BLUE SPREAD (25 TP) * They only ever have 2 SPELLs/

Cover a 6x6 square area in blue Styles, regardless of LV.
squares. A character that exits a blue * When they ACT, they generally apply
square takes MG damage and removes 2d6 Mercy with no modifiers.
the square. This triggers for every * They (by default at least) don’t
square they leave. All blue squares remember SAVING and LOADING - though
disappear at the start of your next they are healed when the party SAVES.
turn. Styles that affect a target cost
double and trigger every time they The reduced number of SPELLs is just
take damage from this SPELL. to make them simpler for combat. The
change to ACTING is because as the GM
Styles you have much more information than
Blue Attack (-4 TP) - Apply to an the players about what ACT would be
offensive SPELL. It can only affect effective, simply declaring it to be 2d6
targets that moved last turn. This no matter what means you don’t have to
Style cannot be taken normally, it can decide how much information to give
only be applied permanently. the players based on the ally’s ACTs.

Orange Attack (-8 TP) - Apply to an For all other purposes, treat the
offensive SPELL. It can only affect allies as if they are player
targets that didn’t move last turn. characters. They generate TP for the
This Style cannot be taken normally, it party as normal, count as a player for
can only be applied permanently. calculating encounter difficulty, etc.
It is up to you whether the players
controls them in combat or not.
( 30 )
 Quirks
Quirks are an addition to the Skill
+1 Quirks can be quite vague and
useful. However, it should still be more
specific than Skills themselves. For
System that help distinguish example “smart” would cover pretty
characters more and represent their much every INTELLECT roll, and so is
particular talents and areas of too broad even for a +1 Quirk. These
expertise. When a Quirk is relevant, it will come up many times per session.
is added to your Skill for a roll, such
as Skill checks and ACTs. Quirks range +2 Quirks should be more specific,
from a bonus of +3 to a penalty of -3. representing something that is less
The more situational the bonus or likely to be useful on the player's
penalty is, the bigger the bonus or adventures. These should only come up
penalty. Only one Quirk can apply to a once or twice per session, across the
given roll at a time, use the biggest one entire party.
that applies. If both a beneficial and
harmful quirk applies, they cancel +3 Quirks should be even more
each other out. specific, they are often some kind of
very niche ability or interest they
By default, when you introduce this have. These should only be relevant
feature, the players gain up to three once every few sessions, across the
beneficial Quirks, subject to your entire party.
approval. Each Quirk must give a
different bonus, so a character that Harmful Quirks (-1, -2, -3) should be
takes the maximum of three beneficial about as specific as the equivalent
Quirks will have a +1, a +2, and a +3 bonus.
Quirk. For each beneficial Quirk, the
player must also select a harmful Power Increase
Quirk that gives a penalty. While Quirks do have a downside,
players will naturally avoid
Particularly for MONSTERs, Quirks can situations they are bad at and
also represent the biological or semi- target situations they are good at,
magical abilities they have. For making them overall a power boost.
example, MONSTERs with wings are You may want to raise Max Mercy by
assumed to be unable to fly, but having about 10% to compensate.
wings might still help them float down
safely or jump farther.
( 31 )
Tier Sample Quirks These samples aren’t universal. For
Mathematician, geologist, example, in a game where the main
astronomer, moss expert, bed enemies are all plant-based,
“botanist” might be too broadly
+3 inspector, painter, sculptor,
applicable to be a +2 Quirk, and
flower expert, singer, guitar
player, Dragon Blazer’s instead might be better as a +1 Quirk,
superfan or not a Quirk at all.
Artistic, computer nerd, These also aren’t entirely literal, a
historian, botanist, biologist, character can have the “detective”
doctor, farmer, physicist, weak Quirk from simply being a fan of
+2 wings, swimmer, car enthusiast, mystery novels, they don’t need to
great jumper, cook, iron actually hold a job as a detective.
stomach, sensitive hearing,
night vision As another example, a “trusting”
Mischievous, empathetic, character might also have trouble
detective, occultist, sneaky, convincing other people someone is
+1 smooth, brave, animal whisperer, lying, even after they figure it out,
fast reflexes, logical since it goes against their nature to
make accusations.
Honest, loud, unexpressive,
-1 trusting, compliant, oblivious, Example Uses:
cowardly, poor speaker “Logical” might apply when solving a
Hates exercise, poor reader, puzzle or making a logical (rather than
-2 can't resist food, bad at math,
poor balance, pop-culture
emotional) argument.
illiterate, paranoid Cowardly would apply a penalty to
Can’t swim/weak to water, fear situations that require bravery, like
of mice, terrible sense of balancing by the edge of volcano, or
direction, stage fright, bad with trying to convince someone
-3 names, fear of heights, doesn’t intimidating.
understand sarcasm and
metaphors, bad with kids

( 32 )
 DISCLAIMER AND
CONTACT
This ruleset by Icebrick1.
UNDERTALE and DELTARUNE by Toby
Fox (and others).
Art taken from UNDERTALE and
DELTARUNE.
This is an unofficial project not
associated with Toby Fox or the
Deltarune team.
Feel free to comment with questions,
concerns, etc. via discord at
“icebrick1” or via email at
“extra.icebrick@gmail.com.”
I am interested in putting custom art
into DELTAROLL - but lack artistic
skills. Let me know if you’d be
interested in helping. Unfortunately
I can offer no rewards save glory.

( 33 )