Lucius Cypher said
From my understanding, Grey Wardens are basically Ghoul's, but don't succumb to the taint as quickly. They do go insane after a long amount of time, if you're male. If you're female, you go Brood Mother instead. That's why they have to go through the Calling; so that they won't succumb to the taint before they lose their mind. Only certain Wardens managed to withstand the Taint for so long, and the only person I remember was able to do that was a Blood Mage, who used magic to extend his life.If Alister survives the take over of Fereldan, either he'd do his own Calling (And thus be dead), or succumbed to the Taint and becomes a very powerful Vanguard for the Archdemon (And thus be our enemy). Or he could just be alive and still trying to defeat the Blight.Additionally, since Alister is a Grey Warden, he's already immune to the Taint. Cause he already has it. He can't get anymore "Infected" at any given time, unless the RP takes place a few years after the Blight in Fereldan and he's like forty years old or so. Ruck went insane because he was just a normal dwarf who began to eat the darkspawn corpses and got infected by the taint that way. Grey Wardens need a special mixture to gain an immunity from the taint, which involves taking on a weaken version.