Kyoukai Senjou no Horizon – Kimitoasamade - Volume 1B, Chapter 5: Socializer at a Place of Learning

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Hao Yan Che is an immortal and Yuan Gun Gun is a mortal.

He died in his first life, as an ordinary human inside an ordinary planet.

In his second life, he swore to live a life of supreme power, and so he did. He reached the apex and exterminated his enemies to oblivion.

Dying, he was reincarnated in a world which could use Chakra. He became The Overlord Of Every Being, Ruler Of 6 Universe.

Unfortunately, he died. Using a mysterious method, he was reincarnated once again inside the world of Tales of Demons and Gods.

Nine harmonic zither chords shook the universe, who dared to not acknowledge the lord?