User blog comment:Pbnjelly/CCC4: Vis, the Elementalist/@comment-7709681-20140706015941

He reffers to Kael'thas Sunstrider from the WoW, from "Kael, the Invoker" from DotA 1 and DotA 2 is based on.

Yours would be a downgrated version, but your friend may be seeing them as similar due to the ultimate, beyond that they are not similar, so don't worry. :P