Payment For Arrogance.

If the sun god had failed his ascension, his divine kingdom won't just stop dimming, it will come crashing down and break apart due to the death of the god. So the sun god is alive but he is hiding. He became a Celestial and decided to send himself into exile. 

This dimming of the divine kingdom is not a small matter. It is something that gods do when they are desperate. It is a self-preservation mechanism that comes at a great cost. It is not something that is to be done lightly but it seems the sun god is highly motivated to avoid a fight with him.

The Celestial Supreme began to mock the cowardly sun god. He called the sun god stupid and then cowardly. His voice spread out throughout the divine plane to all that would hear. He wanted them to know what a Coward the sun god is being. He also wants them to witness the death of the sun god if the coward decides to fight.