User blog comment:Kigal/Vilo'terah, the Embodiment of Unity/@comment-46.115.41.68-20130314053708/@comment-7086206-20130315022837

He gains "damages" their mana and their health, while being restored health. So rather than stealing mana like health is stolen, he damages their mana while being healed health-wise.

And on the terms of your passive idea, it's a great idea, but I think I'm going to switch some things around, moving the marks to his passive and moving his passive to his ultimate.