Enhanced Mercer VS Kratos, Warchief thrall, Alec Mason
Mercer gains the blade of Olympus, Links Golden Gauntlets (transform with his body into shoulder pads or greavers if he forms his arms into something gauntlets would not fit on), Coles lightning powers and Dante's speed/agility/reaction time.
If mercers form is destroyed once, e.g. smashed into putty he loses, he cannot regen from almost nothing like
Spoiler:
at the end of Prototype
Kratos is how he is recently, including GOW 3 shown feats and weapons, ofcourse, he has not got the Blade of Olmypus since Mercer has it.
Thrall has all shaman and warrior powers from WoW as well as his other showings.
Alec Mason (Red Faction Guerilla) has all weapons, backpacks (can use any of their effects) and is invulnerable until the other 2 are dead, in which case he is as fleshy as any human.
http://community.redfaction.com/weapons
Go through the "weapons of the week" pages above to see all the backpacks and weapons of Mason.