Demon Gods.

Demon kings are as powerful as Origin gods except that they don't have true immortality. Demon gods on the other hand are more powerful than normal Origin gods and they also have true immortality. But that isn't good enough for them. They are the equal of origin gods with Supreme laws but they can't match world gods. So demon gods want to become chaotic entities. They want to be feared as world-enders and eldritch beings.

The path to becoming a Chaos entity is very tricky. Demon gods need to evolve to become chaos entities but the assisted evolution of demons ended when they became demon kings. That is the maximum level that their mark of sin can take them. The rank of demon kings should be the last rank for demons but then they force themselves to evolve by fusing with their mark of sin.