Cannibalism is the act or practice of species eating the flesh or internal organs of their kind. In the story, scenes of ghouls eating ghouls and humans eating humans pass regularly as the narrative continues.[1][2]
Strictly speaking, one-eyed ghouls (Artifical) always have to cannibalize since they are forced to eat human or ghoul meat. In their case, however, only eating ghoul meat is typically treated as cannibalism.
Ghoul meat tastes disgusting to ghouls, but in contrast to other non-human nutrition, they are able to digest it. Continued cannibalization may trigger a mutation in Rc cells, resulting in turning them into kakujas.
Effects on Ghouls[]
If a ghoul engages in cannibalism, it absorbs the Rc cells of the cannibalized ghoul, thus increasing the concentration of Rc cells within the ghoul consuming them. If repeated often enough, there is a slight chance that this will trigger a mutation in the Rc cells of the ghoul and lead to the formation of a new armor-like kagune. Individuals with such a kagune are called kakujas, whereas this special kagune itself is referred to as a kakuja kagune. Using a kakuja kagune increases a ghoul's power substantially.
However, kakuja ghouls who use their kakuja kagune often go insane.[3] It is unknown why some ghouls are able to remain sane and others are not, although it appears to be related to the completion level of their kakuja kagune; those with a complete kakuja kagune were all shown to be sane, and Ken Kaneki was able to retain his sanity while using his complete kakuja kagune (whereas previously, he went insane while using his incomplete one).