Ghouls  (gūru, translates to eater species) are a carnivorous and cannibalistic species that are only able to feed on humans and other ghouls. They are very close to humans : They normally have the same physical appearance and intelligence as a human but not the diet, mentality and inner biology. If certain rare conditions are met, ghouls and humans may even be able to have offspring (see One-Eyed Ghoul), and a ghoul's organs can be successfully transplanted into a human.