At the end of the second season, it is revealed that Pangu, the creator of the universe in Chinese mythology, is not a single entity, but rather, a clan of divine beings who are all first generation vampires. Unlike others, these vampires do not need to feed on blood to survive. It is hinted that Cheung San is a member of the Pangu clan. In the third season, two important Chinese mythological figures, Fuxi and Yaochi Shengmu, are depicted as first generation vampires.
The script for My Date with a Vampire was written by Leung Lap-yan in 1997. Leung attempted to market the script to TVB but was rejected, so he went to ATV instead. Chan Sap-sam, who wrote the script for the two sequels, revealed that Lam Ching-ying, a prominent cast member in the Mr. Vampire franchise, was their original choice for the lead actor, and that Joey Meng did not have a place in their initial cast list. However, after they finalised the script, they were unable to contact Lam, who was critically ill. Besides, ATV's top management was not pleased with the script because they felt that it did not fit people's impressions of how vampires should be like. ATV's top management wanted to cancel the project after Lam died of liver cancer in 1997. Faced with these problems, Chan decided to make bold changes to the script and create a new character - Ma Siu-ling, a female ghostbuster wearing high heels and a miniskirt who is greedy for money. Sin Chi-wai, the producer for the series, recommended Joey Meng to play Ma Siu-ling. When Eric Wan was offered to play the male lead character in the series, he wanted to turn down the offer because he felt exhausted, but eventually agreed as he became more interested in the story.
The vampires depicted in this television series trilogy are based on the Chinese jiangshi and the western vampire, although they resemble the latter more. They are creatures that do not belong to the Trailokya or any of the six domains in the desire realm as described in Buddhist cosmology. They do not age and need to regularly feed on blood to sustain themselves. They may also possess powers such as superhuman speed or the ability to shapeshift, in addition to their "immortal" status. Their powers and invulnerability to sunlight, religious symbols and other things that typical vampires fear, however, become weaker as the generation gap between them and Cheung San (the progenitor of all vampires) increases. An example to illustrate this concept of "generation" is as follows: Person A, who became a vampire after being bitten by Cheung San himself, is known as a second generation vampire. Person B, who became a vampire after being bitten by Person A or another direct victim of Cheung San, is a third generation vampire, and so on.