This card is based on Zombire, an American comic book superhero in the original manga. Zombire himself was based on the real life American comic book superhero Spawn. The effect of "Zombire" that causes it to lose ATK when it destroys a monster by battle is a reference to Zombire's backstory, in which he is slowly losing his life.
This card is much like an earlier form of the HEROarchetype. He is based on an existing superhero and gains power through fusing. This is further reinforced in "A Hero Emerges".
The monster is one of the fictional characters in the Yu-Gi-Oh! manga that didn't debut in Duel Monsters. Another example of a monster that wasn't originally from Duel Monsters is "Dark Master - Zorc".