User blog comment:JBox2D/A dedicated anti-mage champion/@comment-4714821-20140223020109/@comment-24090662-20140225083517

Karthus certianly would.

Not sure Ryze would, because Feedback stops him from rapidly casting the way he wants to, and she can still block at least one Q and throw it back at him. It'd probably be an even matchup, given that both of them are high dps. The only thing I'd see that tips it in Ryze's favor is that she's melee, so his snare would stop her from hurting him.