Cultivator?
Evil Spirit?
Demon?
No, none of them seem fit!
As for something like the essence of the Sun...
Zhao Runzu didn't believe in such things. Becoming a Great Demon, he had acquired quite a lot of information; and in the whole world, the only one called the Sun was the 'Fierce Monarch' among the Emperors, but the Fierce Monarch was different from the other Emperors. Although there were those who worshiped Him, He did not concern Himself with The Mortal Realm.
It could be said He had absolutely no interest in the matters of living beings; in His presence, all things were equally insignificant.
This was definitely not the Fierce Monarch.
Yet, the horror lay therein, for Zhao Runzu truly felt that the figure before him was no different from the Sun.
"Evil Demon?"
The Sun emitted a sound that exploded like thunder right beside his ear.