JoJo Zenkichi is the adopted pet of Watake Zenkichi's parents and is a baby chimpanzee that never ages. He is known to be fussy, picky, baby-like, whiney, and demanding. Although a chimpanzee and his age never growing, he was a test subject of Umbrella before and was given the ability to speak all be it broken English and his voice high pitched and childlike. He was constantly spoiled by Watake's family to the point that JoJo is basically the foster brother of the Zenkichi family. However, JoJo's powers proved to get the better of him years later, when he begins to expand into a giant gelatinous mass of fat and unintentionally murders his masters/parents, and was taken to the zoo and remained there with his reunited mother, who was not a big fan of taking care of children, all because his masters forgot to buy some ranch for his carrots. When his behavior towards the other chimpanzees, animals, and people alike worsen fast, he was abandoned at Louisiana by the zoo's manager and left there neglected. When he encountered Ethan Winters during a meal, he demands to see his "mama" immediately. Ethan, trying to explain, points out that he has a wife to bring back. But JoJo wasn't having it. Ethan, sick and tired of his tantrum, bluntly and angrily scolded him for being a narcissistic, spoiled, entitled ape with no logical senses and tells him why he's constantly neglected. Not only does this make JoJo stop, but it also made him cry, sobbing and saying that he's just too scared to lose someone he loves again and just wants to feel a bond with someone. Ethan, returning his composure, calmly reminds him that he's still loved and just needs to be disciplined properly. After surviving the Baker Residence and helping defeat Evelyne, he is currently living at Hope's Peak High's Daycare Center and forming a strong bond with Watake to the point that their bond can never be broken.