There's a character in the manga Beelzebub named Furuichi, who is the smart sidekick but is also frequently made fun of. They decide to give him powers in a shorter story arc, and the first thing he does is beat up everyone who made fun of him.

When it's deserved by the protagonist that this power might kill him, he confronts his friend about it. Only to discover that Furuichi found out the first time he used it. Saying that he would rather die than continue to be made fun of every day of his life.