[quote=21308]
Oh, I must have forgotten about the part where the archdemon is the only one capable of having control while it's around. Alright, so we'll scrap that part. Maybe he just ends up taking in an unprecedented amount of the darkspawn taint, kind of like Ruck. Does the game ever say what would happen if a Grey Warden were to be put in a situation like that? I'm assuming they wouldn't just die or go insane, or at least not as quickly as or in the same way a normal person would.
[/quote]

One of the DLC stories in DA 2 deals with a highly corrupted Warden. That one did essentially become like Ruck but he retained more of his intellectual faculties It took a powerful darkspawn to force him to succumb to the taint before his time. Normally they can resist it into their 40s or 50s so unless there is some corrupting influence, Alistair would be far too young.