Mainly based on the games with a little history taken from the books.

Flynn (Fly) Taggart joined the Marines at 17 and dedicated his life to the the Marines. After being court marshalled for attacking a superior officer in order to stop civilians from being fired on Flynn was transferred to the UAC on Mars. That's when all hell broke loose literally. After fighting the hordes of hell on both of Mars' moons and in hell Fly went back to earth only to find it had been invaded by demons and they had killed his pet rabbit Daisy. It was then he made his vow, he wouldn't stop until every last demon in the universe was dead....  Rip and Tear.

Flynn lost himself in the fight, years went by, his suit was upgraded, his armor, his weapons and thanks to the divinity machine he became a god, no longer needing to eat, sleep, or drink as he wadded threw the armies of hell destroying everything in his wake. One thing he never saw coming was the end.

There were no more demons left, hell was empty and there was nothing left to rip and tear. A portal leads him to a new earth, one that has never heard of demons or argent energy or the Doom Slayer. The question is now what? Who is he? He doesn't even remember his name all he remembers is daisy and the destruction, the endless fight. When you've transformed yourself into a god of destruction and rage what do you do when there are no more demons to fight?

FC: Karl Urban