Board Thread:Warhammer 40k General Discussion/@comment-28917471-20140706092250/@comment-6078851-20140731131932

i think sanguinius would've made a better warmaster than horus, but he suffered a pretty exceptional mutation (wings) which may have made him easier to corrupt than horus if the gods had concentrated all their will upon him.

personally i think el'jonson would have been/is the hardest primarch to corrupt. although i also think a heresy would have happened regardless of who was warmaster: if the warmaster wasn't corrupted another primarch would have been, but because that primarch wouldn't be warmaster the heresy may have lacked the potency of horus' heresy.