Kyoukai Senjou no Horizon - Volume 1, Chapter 13: The Authorities at the Rendezvous Point

This story is set during the end of the Sui Dynasty, a time where multiple powers struggled for supremacy and power.

Into the fray enters two orphans Kou Zhong and Xu Ziling; these two youths by many chances and luck obtain ‘The Secret to Long Life’ allowing the two to obtain profound martial abilities and a chance to rise to the top in this age of turmoil.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

As we all know, there is a force that must not be messed with in the Southern Region, thatched cottage.

Among them, the eldest disciple is the Qingyun Sword Master of the Southern Region, with a mastery of swordsmanship.

The second disciple, the Eternal Empress, leads an era.

The third disciple is a great Confucianist in the world, and the star of Wenqu came down to earth.

The fourth disciple, the reincarnation of the demon god, suppressed Jiuyou.

…

Lu Changsheng: Me? I am nothing special, just their master.

- Description from novelbuddy

Lugh woke up to find that he had transmigrated to a hundred million years later.