Ymir’s avatar, in my opinion, is the strongest overall by in game measure (ability to destroy buildings, destroy ground enemies and traverse environment). Also it’s the only one actually armed.

I also view gods by who worships them, the mighty frost giants follow Ymir and would imagine that any slimy cold-blooded snake man wouldn’t go anywhere near to the cold regions of Ymir. You could even suspect that the serpent men of the volcano are trapped on all sides by Ymir as the heart of the volcano is the only safe place from Ymir’s bitter cold.

From another source: “Dread Ymir rules icy Valhalla, a realm of long halls, snowy glaciers and eternal drinking, wenching and fighting.” That sounds pretty great to me.

On a less serious note, I think Conan would have great difficulty fighting Ymir and it’s followers because Conan would have to wear a shirt.