Were Swain and Irelia meant to mirror each other?
Just something that came to mind when I was reading through Swain's background. From Irelia's quotes, her family and friends were killed by Noxus, causing her to ruthlessly defend her homeland. But for Swain, his own ruthless defense of his homeland led him to kill his own family. It's an interesting situation.
Irelia also seems, basically, to not be entirely certain in her role. In her voice lines, she's sometimes not sure what to say to her followers and expresses horror at the thought of people seeing her blade dance in anything less than a perfect state. Swain, in comparison, is utterly composed. For Swain, it is not anything within his power to effect or see that worries him, but anything without.
Compare the line 'You do not know burden until you've seen a thousand people hanging on your every word.' and 'I've killed more men with words than by my own hand. Not for lack of trying'. Both acknowledge that their roles give them huge influence over the fate of thousands, but while Irelia secretly worries about her abilities in that regard, Swain has no such hesitation. I'm starting to suspect Swain suppressed his demon through sheer force of self-confidence.