[Taqwus]

*shrug* Again, lightning immunity is cheap to put onto any commander with a spare misc slot.
A Bane Lord with a Ring of Tamed Lightning and an amulet of magic resistance would probably do it for cheap -- takes only 1 air, 1 astral, a couple death. Comes with a magical weapon so mistform is meaningless, will laugh off the wrathful skies, has good enough MR to ignore the phantasmal weapons and to bypass blood vengeance, and doesn't get tired.