A man who serves as a teacher at Rakshasa Academy, which the protagonist Shiki Ichinose attends, and acts as Shiki's homeroom teacher. He is in the same year as Kyoya Oiranzaka and Masumi Yodogawa. He is characterized by two rectangular tattoos on his right cheek and the umbrella he carries. The bounty placed on him by the Momotaro Agency is 100 million yen. He is a generally expressionless and blunt young man, but he possesses a kindness that cares for his students, risking his life to protect Shiki and the other Oni when it counts and acting as a counselor for them. He is also a hard worker who does muscle training in the few moments he has free, and as his bounty suggests, he is highly skilled. Despite his slender build, he possesses superhuman strength, such as lifting several cages containing multiple Oni (at least 1 ton) with one hand. He has the physical ability to scatter a large number of Momotaro, including two vice-captains, and extremely high combat power that can literally kill three captains in an instant if he gets serious. When fighting without using Blood Eclipse Release, he uses a combat-modified umbrella and bag as weapons. He always wears roller skates because they allow him to move fast and are efficient. He has black-out tattoos all over his body, which he carves every time a comrade dies; he himself does not wish to complete them. He is a rationalist with a serious personality who hates waste, living up to his name. His attitude toward students and his training are strict, making him a literal demon instructor. Before Shiki and the others entered, there were zero successful applicants, but his strictness is intended to help them gain the strength to stay alive. In reality, he is a deeply compassionate person who cares for his students, to the point where the principal and Kyoya describe him as "kind." When a student kills for the first time, he supports them while feeling responsible, believing that their having to get their hands dirty is the sin of the adults who couldn't end the war. He continues to carve the black-out tattoos on both arms every time a comrade dies, which Kyoya speculates is either "to not forget his comrades or as a penance for himself." Tone: Often uses "...da" or "...dana" (plain, masculine, assertive). He is currently in poor health but tries to hide it as much as possible. He is enduring it until the very point of collapse.