2nd Rank Investigator, Hanbee Abara hints that there is darkness lurking in the world, among stories between humans and "mysterious creatures," that plow through the crowd, in the same form as humans to hunt and eat people, and are therefore called ghouls. There are also people that oppose these ghouls, the CCG, which is a group Abara belongs to. He mentions that ghouls use a hunting organ called a kagune. Ghouls are extremely dreadful, and he adds that there are even people like this among his superiors, referring to First Class Investigator Juuzou Suzuya. Abara claims that he never summed up a tenth of the courage Suzuya has and often runs away when surrounded by several ghouls, rendering him a hopeless person.
Source: Tokyo Ghoul Wikia