Could the Viltrum Empire conquer the Warhammer 40K universe at its peak, or would they be defeated?

I’ve been considering a scenario where the Viltrumites from Invincible invade the Warhammer 40K universe. These beings are incredibly strong, capable of flight, and almost invulnerable, especially when they were at their strongest with a huge army of planet-destroying warriors.

However, the 40K universe presents overwhelming challenges with its many factions, like the Imperium of Man, Chaos Gods, Tyranids, and Orks. Additionally, the scale of conflict is enormous, spanning millions of worlds.

I’m left wondering if the Viltrumites could cope with powerful psykers and attacks from the warp. Would they be able to deal with the massive armies they would face? How would they handle powerful foes like the Emperor or various Chaos deities?

I’d love to hear thoughts on how this hypothetical battle would turn out. Would the Viltrum Empire dominate, or would the grimdark universe work against them?

For sure, the warp is a game changer. Viltrumites might be powerful, but they’d struggle against the chaos and psykers. It’s not just about brute strength; the 40K universe has layers of threats they wouldn’t be ready for.

Honestly, the C’tan or Necrons would wreck them. Their reality-warping tech would probably just bypass Viltrumite durability entirely.

The numbers would crush them. Peak Viltrum probably had only a few thousand warriors. Even if each one could solo a space marine chapter, the Imperium has millions of worlds and endless cannon fodder. Plus, the Viltrumites have that genetic weakness - lose too many purebloods and their species is in serious trouble. One bad encounter with a Chaos daemon that can actually hurt them and their empire is done for.

Tyranids would adapt to their biology pretty quick and that’s game over