MTL - Flower Master in the City - Chapter 2922 Kill it anyway

Everyone said that Yi Qing was the number one Sword Cultivator in the world, with a swordsmanship and cultivation that no one could surpass. Whether it was when he was cultivating in the Lower Realm, or when he was in the Ten Heavens of the Upper Realm, he has always been undefeated.

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.

The Revered Master, Yu Yan, known as the number one in the cultivation world, waited for sixteen thousand years, and finally took in a disciple. He taught her carefully, and took care of her diligently. He watched her as she slowly grew stronger as she comprehended the laws, and just as she was about to soar into prominence… she died!