Tank Chair manga volume 3 features story and art by Manabu Yashiro.

In the parapsychic space where Nagi communes with Sensei, a black mass hangs ominously, symbolizing the bullet that pierced his brain, and the losses that came with it. Sensei wants Nagi to become a perfect vessel once more…or else, they have no use for him. Yet Nagi defies Sensei and vows to live an imperfect, human life, setting himself and Shizuka on an irreconcilable course to a cataclysmic confrontation…