Champions

[Kaden]

I can't recommend Ryze too highly, as far as damage is concerned (and assuming you don't mean AD). If you keep up with the other folks, a set through your spell-combo can easily take out 50%-75% of a person's health.

Honestly, I'm guessing you're not doing his combo correctly.

Q>W>Q>E>Q>R>Q

At the end of that, both Q and W should be up at about the same time. Between spell casts you just walk along whatever path the enemy will be taking so they don't get out of spell range. One of the developers described Ryze as a "spell machine gun" and that's exactly what he is.

EDIT: The great thing about Ryze isn't just his damage output (which is good) it's that he gets that kind of damage while building items that increase his defense (Frozen Heart and Banshee's Veil, for example). He's really the only caster that gets to do that.