Just a quick question.

Warhammer Fantasy and 40k shares many concepts and elements right? Both have Orcs, Both have Chaos forces, etc.

Regarding the Foreces of Chaos Warhammer Fantasy has their Big important chrarcater by the name of Archaon the Everchosen:

https://www.youtube.com/watch?v=2nJFSZPUH-4

My question is who is the equivilant to Archaon the Everchosen in the 40k universe?

Abaddon? http://warhammer40k.wikia.com/wiki/Abaddon

At least I think it was when I played the miniature game in the 90s.

Seems to fit the bill.

I was thinking it was actually Horus but Horus is dead I think?

Now I wonder if they will use him for Dawn of War 3?

Unless DoW 2 already did it?

No! 40k has Orks. It's still chaos in the future tho not Kaos.