I believe Irredeemable came first. Both series are written by Mark Waid, and if one didn't come after the other, I believe they were both written at the same time.
Irredeemable is about a Superman-like superhero, The Plutonian, who becomes corrupted: he starts murdering, takes the world over in his own way, leaving death, and destruction in his wake. The stories were meant to parallel each other: one falls, one rises.
I own Irredeemable via Humble Bundle and never really made it a priority. I was more interested in Incorruptible, the story of Max Danger, a supervillain who gets his own redemptive arc. This is, in fact, the story of Max Danger trying to save the world from The Plutonian. I'm actually super into redemptive arcs. Stephen Strange's origin story is a redemptive arc: he wasn't a villain, but he was a giant jerkface. He was brought low to learn compassion - and the mystic arcs - and became a much, much better person. Somehow, starting him off that way wouldn't be the same. He had to learn humbleness and to value human life, and those lessons made him far humbler than if he'd simply started out that way. Having worked so hard to become so much better, he's less willing to let that slide.
Redemptive arcs can be amazing. Max Danger is no Doctor Strange. He's got a long way to go, but he was motivated to do this himself, and he's got less of a support system. So far he's doing fine, this is funny, this is entertaining, and it makes me think about what a supervillain would have to go through to make him change so drastically.
It's just the kind of fun I needed today.
That and Whirl orgies. So many Whirl orgies.
But I decided not to taint BL with that messed up thing I have for Whirl. Not that much.