- Kōtarō Amon (亜門 鋼太朗 Amon Kōtarō)
- Voiced by: Katsuyuki Konishi
- He’s a Rank 1 Anti-Ghoul Investigator and a friend of Mado. He has a very strong sense of justice and believes that he must make this ‘Wrong World’ right by killing the ghouls whose murders create orphans. He is very dedicated to his job and begins to work even harder after Mado is killed. He fought Kaneki but he lost; however, Kaneki let him go.
- Hideyoshi Nagachika (永近 英良 Nagachika Hideyoshi)
- Voiced by: Toshiyuki Toyonaga
- Nagachika is Kaneki’s best friend, nicknamed “Hide”. He has a sharp intuition, so much so that while Kaneki tries to keep his ghoul identity hidden from him, Nagachika seems to know something is weird about his best friend. After Kaneki disappears, Hideyoshi joins the Anti-Ghoul forces in order to learn about his whereabouts, eventually being promoted to Rookie Investigator and partnered with Amon and Akira.
- Kureo Mado (真戸 呉緒 Mado Kureo)
- Voiced by: Tōru Ōkawa
- He’s an Anti-Ghoul Investigator with the rank of Senior Investigator and he works with Amon to achieve his goal. A very experienced and ruthless fighter, he is more than a challenge even for the physically superior ghoul and always trusts his intuition, which is never wrong. His ultimate downfall came from the fact that he was obsessed with ghouls (or rather dissecting them) and while fighting Tōka and Hinami he let his guard down by his fascination with the latter, being killed by them. His daughter, Akira worked with his partner after his death. His goal was to get revenge on the “One-eyed Owl” ghoul for killing his wife.