Would the Doom Marine be able to survive in the world of Warhammer?

Depends on who's writing the fanfic. The 40,000th Butthurt Legion will claim Doomguy is, at best, a Kasrkin or something dealing with infinitely less powerful versions of demons than in 40k because woe to the poor faggot who doesn't worship the poorly written shit pressed out of the unwiped asscheeks of the Black Library fiction.

I picture the 40k, with its space marines and Tech priests all marvelling/envy/disgust at the sight of doom guy for various reasons

He's what's in the Grey Knight box.

You decide if that qualifies as "survives" when he's the final solution when all else fails.

no fuckin way

He rode a massive point blank explosion that ruined the majority of the surface of a planet and sent him across dimensional barriers.

Most "Doomguy in 40k" usually just devolve into how badly he fucks the warp up.

Would the world of Warhammer be able to survive the Doom Marine?

Doomguy's a bit of a paradox because he uses demon-enhanced power armor, and is fueled on by demonic magic he consumed from destroying demons.

But he's also extremely pro-human, lead an order of hell-paladins, hates anything demonic, and has not become a demon.

So how this would work in 40k would be weird. He'd essentially be the only successful example of "use Chaos against Chaos".

>devolve

I think you mean "explode with awesomeness"

and if the imperium decided WOAH THERE THAT'S HERESY I don't think he'd give a fuck. He'd rip and tear through every fucking smurf they sent his way and be thankful for the free boltguns doing it.

thats really the question here