User blog comment:Masterzach32/Yomu - the Dark Wind/@comment-7709681-20140131010404/@comment-24132411-20140131030739

Ok, I see where your coming from, maybe I need to be a little more clear.

So the chance of the ultimate killing the champion is increased by their missing health

So a level 3 ultimate would have a 50% chance of killing a champion with 100% health missing, and a 25% chance with 50% health missing.

I also added an AP scale to the armor from his E.