Children of the Holy Emperor - Chapter 100

The sky was painted gray forever. The light of the sun was restrained. The darkness of the night was deeper than ever. At such a time, he belonged to a class people didn’t even recognize as ’human’. He was at the bottom of the social stratum, a slave. And when his only family was taken away from him... he no longer had a purpose in life. Yet, he clung to life because of his promise. And he set an impossible goal for himself, just so he’d have an excuse to live. When he finally reached a place he never expected to be, in pursuit of a purpose he expected to fail and die miserably trying to fulfill... he awoke to a night that would change his entire life. He was an insignificant fly, a mere speck in the destruction of the Empire. But he... survived. And, despite being a slave, he gained the blessing of a king. Or rather, the curse...

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

The heavens and earth change when the blood phoenix descends.