Raszageth a.k.a the the Storm Eater, the Storm Bringer, the Storm Goddess.
So far she's proving to be a amazing villain in appearance, power, and motives.
Appearance - She looks very unique and interesting. A good mix between a dinosaur, dragon, duck, and bird.
Power - Easily one of the strongest villains we ever faced only behind Sargeras and N'zoth. Powerful enough that a single attack could one shot Alexstrasa and Kalyacos. Powerful enough to make Deathwing and his Elite army chicken out instead of facing her head on. Wind powers that makes the one from Ak'akvir look like child's play and lightning powers that makes Lei Shens lightning look like a amateur.
Motives - She's extreme but she has a point. Bring the world back to the natural order and down with the wicked magic! I agree with my storm goddess. You want fear? She's the fear! You want chaos? She's the chaos! You want a new beginning? She is the new beginning!