Kluh is the latest of Hulk's many villainous alter-egoes to surface in the Marvel Universe and an antagonist in World War Hate / Axis.

Kluh is described somewhat simply as "Hulk's Hulk" - a being that gives in completely to anger and hate, this makes him similar to Savage Hulk and Devil Hulk but his appearance is even more demonic, though he is considerably smarter than Savage Hulk.

Kluh enjoys being a villain and is a violent brute who even expressed his belief that what was wrong with the world's heroes wasn't that they were "bad" but that they weren't "nearly bad enough".