Tank Chair manga volume 1 features story and art by Manabu Yashiro.

Living on Gui Cheng Island, called “the most dangerous city in the universe,” is no easy task. Genetic doping is common for gangs to gain ultimate power. Shizuka, a young girl, takes on the most dangerous of assassin jobs, but she's not the one doing the killing. Rather, it's her brother, Nagi, a strong assassin who took a bullet to protect his sister, leaving him in a comatose state and having to use a wheelchair. However, Shizuka has figured out the key to waking her brother up: he must be faced with killing intent! Thus begins a violent journey of recovery, battling the most dangerous foes!

Tank Chair manga volume 2 features story and art by Manabu Yashiro.

“Fail me again…and you will be graduated.”

Nagi and Shizuka have managed to avoid a grisly death at the hands of two assassins--siblings from Nagi's past life enrolled at the mysterious ACADEMY. To make safe their escape from this terrifying duo, Shizuka moves them across Guicheng Island, from one safe house to another. But Nagi's whereabouts have reached the ears of the leader of the Academy, an iron-fisted administrator known only as Sensei, who dispatches a prodigy at the art of murder to track Nagi down once and for all: the rampaging rookie, Uzu!

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…

Tank Chair manga volume 4 features story and art by Manabu Yashiro.

The parapsychic duel between Nagi and Sensei on Guicheng Island is over, leaving the physical and mental landscape an utter ruin. Now our attention turns suddenly to three years in the past… Here, Nagi is Sensei's prize student, a prodigy whom no classmate can match. What events led to Nagi and his sister fleeing the academy and incurring the wrath of the world's deadliest being?