Buer, the Black Wheel of Decay (also called Buer, King of the Dead) is a demonic force that is mentioned as the polar opposite to Ka, the Great Wheel of Being. He is one of the most powerful creatures to ever exist, although he is only truly powerful as long as he is within the Putriverse; his total strength would fall substantially if he ever happened to exit his realm, yet he would still remain quite powerful. However, thanks to the work of Ka and Celestial, he is always constrained within his own universe, unable to cross over into the Middleverse.