Too Late.

There was war and destruction going on around him as demons fought gods. But he simply stood in the sky while his body began producing light.

The golden light within him was leaking out through his skin. His skin began to melt. Even his horn was not spared. It is like there was a fire burning within him. This fire is reforging him from the inside out. 

He said to himself in anticipation, "The resistance of the mark of sin has finally been completely resisted. It is mine now."

The source of light within him is the mark of sin. The crown of dominion has acquired enough power through the sacrifice of powerful items to overcome the resistance of the mark of sin and cause his evolution through brute force. It is an unconventional way for demon kings to evolve.