That whole fight has to be the most awesome piece of Warhammer fluff eva...
Archaon: MUHAHAHAHAHAHA! I, Archaon, have defeated Valten! Now to finish him off!
Valten: Oez noez! What will we do? Who will save us? the world is doomed!
*Grimgor walks up, knocks Valten aside and picks up Archaon*
GRIMGOR IS DA BEST!!!!!
*Grimgor walks away*
But seriously, I'd say Grimgor would win. He'd just do what he did at Middenheim that made O&G a "good guy" race forever more.
This is a warhammer forum. Everything is a military operation.
I have spent the last 25 minutes doing reconnaissance on my kitchen for operation: Cup of tea.