The huge drone that Preston Stormer fights in the first season's flashback scenes was actually designed by a fan for the Official Bionicle Building Contest #53, held on the LEGO fansite BZPower.com. The model was originally going to represent a "mystery character" from the Bionicle storyline, possibly the murderous robot called Marendar that was set to appear in the Bionicle online story serials. But since Lego had decided to discontinue the Bionicle line, the winner model was instead recycled into an evil drone for their Hero Factory series.
Although the earlier episodes had a basic continuous story, later episodes threw out the continuity almost entirely, and instead told stand-alone stories, all of which ended in unresolved cliffhangers. The final episode in particular utilized a different design style and replaced all of the voice actors. Some believe this was because LEGO had already decided to cancel the series eventually as early as 2012, and most of their attention was diverted to preparing the relaunch of their more popular BIONICLE toy-line.
Several characters that appear in the cartoon are not based on existing LEGO models. Professor Zib and his floating helper Quadal are prominent characters despite not having toys to promote. Sir Makuro, the giant evil drone, the female reporter, and a bunch of other side characters also belong to this group.
The name of the female operator robot is Lucy.
The name of Makuhero City comes from a play on the expression "make you a hero". This is fitting, considering the city's primary facility is the Hero Factory. It also references its founder, Akiyama Makuro, and to the evil Makuta race from Hero Factory's sister franchise, Bionicle.