User blog comment:SirAston/URF and the LoL Engine - A To-Do List/@comment-24459186-20140403192402/@comment-24459186-20140403192751

Also, I tried out Ryze in a custom match, his Ulti when cast can stack with itself, thus giving him increased Spell vamp and being virtually unkillable aswell as having abilities with no cooldown after 3-4 rotations of his combo on any enemy.

He is literally only limited by his animations, and the rate the game can receive your keystrokes.