Ex-Arm Vol. 4

Written by HiRock with illustrations by Shinya Komi, Ex-Arm is a sci-fi seinen manga first serialized in 2012.
The story begins in 2014 when Akira Natsume, a talented high school student, decides to improve his life and tries to get a girlfriend like his older brother. Before he has a chance, though, he loses his life in an accident. Sixteen years later in 2030, a policewoman and her android partner find and activate a highly advanced AI and superweapon called an “Ex-Arm"…but the weapon turns out to actually just be Akira’s brain!
Akira infiltrates a special ward after the Sexaroid Brothel incident in Vol. 4 when a mysterious new “warrior” appears!
Notice: This manga is written in Japanese.