PookaMustard: Also who the hell came up with "Doomslayer"
It's Doomguy.
idbeholdME: It's Doomguy in the original games. They came up with Doomslayer for the reboot games. As they are not the same character (despite their desperate attempts to make it so), it makes for an easier distinction as to which character you're referring to.
EDIT: If you want the edgy lore behind it....
https://www.youtube.com/watch?v=OA9D32aEO00 Are you sure? I mean, I haven't played the new Doom games, but from everything I've read/seen
I thought it was established it is the same guy.
EDIT: Even the Doom Wiki says "The Doom Slayer is the main protagonist of the Doom franchise, serving as the main protagonist of the original trilogy and it's spin-off, Doom 64. He returns as the protagonist of Doom (2016), Doom Eternal and Doom: The Dark Ages."