When he was younger, E was happy, even though he was sick and weak. He was able to make friends, despite his disease, and was content with his life. However, eventually his left arm stopped working and got somewhat infected, so doctors had to remove it and replace it with a mechanical arm.
When he went to play with his friends, they got scared of his fake arm, so E lied to them saying that it was just a cool toy that he got, which fools them for a bit. As this goes on, E gets tired of lying, saying that he’s “okay” and that his “friends” say they don’t mind his robotic arm. Eventually, E stopped communicating with everyone to avoid scaring more people and hurting himself.
Meanwhile, doctors and scientists are fascinated with how well E is holding up with his fake arm, and decide to do some more tests on him at a private hospital. They perform many operations on him. One operation, for example, involved taking one of his eyes and trying to make it so that his eyesight would be better than most humans, or adding things to his back to see if his back would get stronger. In the end, they only ruined the majority of E’s body, yet the doctors become more and more curious with prolonging people’s lives with machines.
E lives and maintains his boyish appearance for many years, hating all the tests and pain he has to endure, wondering why Death still hasn’t taken him. Since he’s usually so weak, he can’t fight back against the doctors that perform all the operations on him and try to sustain more of his life.
Later, E meets Tanaka and Yamaguchi, who take him away from the hospital, and gives him a chance to enjoy his remaining life without pain, but with friends and family.
A month or so later, E finally, but peacefully, dies
However, as he dies, E regrets that he’ll be leaving his “family”. He regrets that he wasn’t able to spend much time with them, but is happy that he was able to enjoy time with them, no matter how short it was. He hopes that his “family” won’t spend too much time mourning for him, and wishes that they’ll remain happy, even without him.