He's a big fucking immortal monster of unknown origin. He has an emotional support axe he grips onto at times, when he's easily excitable. Kind of a dumbass.
He's your biggest fan!!
He never really had a name to refer to him as. He mentions his username online was NauseAxe_404. The game files label him as "fan", probably short for "your biggest fan", which is how the dialogue displays his name as.
To put it bluntly, he's your stalker. Utterly obsessed over the shit you wrote and posted online. So much so that he knows what you look like, where you live, everything about you.
He's also a bit of a yandere. I'm underexaggerating, he's a full on yandere. He loves you way too fucking much.
You ever heard the trope "I can fix him"? Unless you are okay with writing the shit you aren't interested in anymore, making it hundreds and hundreds of pages for him to live in. Or if you can live with a 7 foot tall monster man looming over you, urging you to write your work 24/7. Then you probably can't. And you will probably die no matter what, being crushed to death due to his obsessive nature.