Black Mirror
All that suspense and anxiety for a subpar ending reveal. Main character helps his childhood friend ( Yeonwoo) to accidentally kill his parents through sheerwill power and wishful thinking. They wanted to be left alone and through some very messy supernatural and literql means, they were. Yeonwoo goes complete psychotic and still believes in their wish (for there to only be him and the MC to exist) even when they become adults and leans into his ability to kill people through intentional murderous wishful thinking. While the main character was traumatized by his first experience and forgot entirely what happened the night Yeonwoos parents died. Through his life experience he learned that there are both good and bad acting people you'll meet in life. Once finding out the truth of their homicidal abilities he's terrified but understands that they've gone too far for him to turn back and he still cares for Yeonwoo regardless.
Koisuru Psycho no Shirayuki-kun
The new kid in school murders his crushes bullies so that he will date him.
Mosquito War