Abu/History

Background
Abu is a high school student who wants to become a tattooist in the future, so he practices doing tattoos on his own body. He attends school with his body retracted into his shell to keep his tattoos hidden from the eyes of the teachers. Thanks to his tattoos, Abu knows he is seen as terrifying to the school bullies and they move away from him when he appears, which does not bother Abu as it is already beneficial to keep these animals away.

One day at school where Kiyosumi, the girl who sits behind him, was facing a group of troublesome students, Abu appears at the place saying that they are in the place where he usually takes his naps. This causes them to apologize and leave the place scared and get Kiyosumi out of trouble. Abu asks Kiyosumi if she is okay and she asks if it is really him, not recognizing him for having his limbs extended and showing his multiple tattoos. Abu states that it is him and retracts his body to show it. Kiyosumi asks if he is some kind of gangster and Abu denies it, and alleges that everyone just moves away from him every time he stretches out a bit. Most of his tattoos are done by himself as Abu explains that he is trying to become a tattooist and has tattooed himself as practice. He reveals that he has always wanted to work on Kiyosumi dangerous horns - horns that when let to grown will stab Kiyosumi in the head and Abu was the only one who realized that she was approaching death day after day.

After school, Kiyosumi accompanies Abu to his tattoo studio. Abu claims that he didn't think Kiyosumi would be interested in something like this and dissuades her from getting a tattoo just to thank him for earlier. Kiyosumi alleges that's not it. Abu declares that she has nice horns and that he is grateful to be able to ink them, but asks if she had considered removing them. Kiyosumi claims that she is not sure and relates that at some point she began to feel like she wasn't able to do anything unless she was told to her, and maybe she has always wanted other animals to tell her what to do. She reveals that she has always wanted someone to save her life, but instead she continued approaching death for 17 years without anyone noticing, like an idiot. Abu begins to tattoo Kiyosumi's horns and tells her that everyone dies eventually, and everyone is too conceited to be worrying about her. Back when he first inked his shell, no one really cared, so he thought that living that way makes life much easier. After finishing the tattoo, which is flowers, Abu invites Kiyosumi to spend the night together to make them bloom. Kiyosumi and Abu spend the rest of the night walking around the city and having a good time.

A week later, Kiyosumi returns to school after a week off from her surgery to cut her horns. She sees that Abu tattooed little blooming flowers on the sides of the "hell" tattoo on his shell, probably as congratulations on making her first decision of her own volition.