I just want a friend.
It didn't matter how far, or how deep he tried to remember the first time of how it happened or why; it was all one big blur. Kenny McCormick couldn't die. At least, he didn't stay dead. He could think of many reasons as to why he didn't like it: everyone is supposed to die, who likes having more than one funeral, when would he find out what God looked like… No, the worst part was that no one remembered. He was sick of trying to convince his friends and family that he was different, he was sick of seeing those he loved be torn over his death and contemplating suicide to be with him but then being happy-go-lucky the morning after, he was sick of pretending like he was normal. He wanted to be normal, not act like he was.
I want a friend.
Kenny McCormick faked his death and disappeared. It was a quick, simple thought that had occurred to him once when he was scraping his old dead body off of the road one day. If they forgot his real deaths, they shouldn't forget a fake one. So he got to work. It took a week of ignoring his friends and family and trying to fabricate a perfect suicide note, but he did it eventually and somehow, somehow… he had managed to fake a suicide.
The escape plan was easier than the facade by means of action, but mentally, it made him feel like he really, really was, gone. Seeing Karen crying over his death… Somehow it was worse than with his real deaths, like he had actually, finally, died. He did, in a way. Now there was no more Kenny McCormick. He had a real life death certificate, a tomb stone that would be in the ground forever- a grieving family that would never recover and friends who would never forget him.
I need a friend.
He was wrong, though. Everyone went back to their normal lives eventually while he was stuck struggling to survive on his own under a new name. It was embarrassing. How could he be forgotten again? It was a repeating question with only one response: now that you're really dead, you can't see them and play pretend again.
Sitting in his own wallow and self pity, he decided that he would overcome this infra dig with a name that would never, ever be forgotten, a name that would make him immortal to people's minds: he would live as the great Mysterion.