
Originally Posted by
Norellicus
Your own quote doesn't support the idea that Sargeras was corrupted by a demon, and most places aren't specific about what drove him mad, so I can't say for sure either that he was corrupted by an old god. But that's generally their MO, so it wouldn't surprise me; it's already clear he was being manipulated by them to some extent, as the Demon Soul was empowered by them, purportedly to set Sargeras free, but ultimately unbeknownst to him the use of the artifact would set them free in the process due to the immense power contained within it.