Zatch Bell was a Mamodo with no memory of who he was. His doll-like face and blue robe make him distinguishing. Found in London and cared for by Mr. Takamine, Zatch returned the favor by promising to help the man's son, Kiyo Takamine, overcome his socially awkwardness even if Kiyo was reluctant to have him around.

Once Zatch learned of his true nature, he was a bit scared at first, but Kiyo snapped him out of it. After the incident with the Mamodo Kolulu, Zatch vowed to be Mamodo King to ensure a happier life for his kind where they don't need to fight. Zatch does try to live a normal life, with the Vulcan-300 (Made by Kiyo from a French fry box and chopsticks) as his favorite toy. When Kiyo reads from Zatch's Red Book, it enables Zatch to shoot lightning out of his mouth ("Zakare"), among other spells.