The title of this article is conjectural!
Although this article is based on canonical information, the actual name of this subject is pure conjecture.
The fat cat is a stray cat that ate Timcanpy. It appears in the first chapter.
This is a fat cat of unknown race with a white fur except around its left ear which is brown.
It is First shown in the hands of Allen Walker in the abandoned church, where he fled, eating Timcanpy. When Moore Hesse joins Allen, the cat that has just been caught is released from Walker's hands and just stands next to him, licking his paw. Soon, Moa faints from the poisonous fumes of Akuma, and Allen is detained as a suspect.
The cat is then shown at the police station, sitting on Allen's lap. After the interrogation, Allen goes with the cat to the house of Moore, where they are attacked by Moa's son-in-law, Mark, who turned out to be Akuma. When the Akuma attackes, the miasma produced by the weapon touches the cat, after which pentagrams of the Akuma virus appear throughout his body. After a few seconds, the animal dies right on Allen's arms.