https://www.novelupdates.com/series/my-big-brother-is-seeking-death-again/

Description

The strongest man of the cultivation world, Yu Hua had sent the Grand Supreme Elderly Lord, Chi Hou to cultivate. After cultivating, Chi Hou was unrivaled for hundreds of thousands of years. However, he was ridiculed by the Demon Lord to be a bachelor who is as old as bone ashes and a fossil grade single dog. Not to even mention a girl, he doesn't even have a little sister. In order to reverse the game, Chi Hou decided to kidnap the Demon Lord's precious sister and turn her into his own little sister. He'll first save her, then raise her, teach her magic, feed her dinner, tell her bedtime stories, and give her rare treasures. Like this, he'll be the perfect brother. She won't even remember her real brother.

Little sister: "What does this pervert who pulls me up every night to tell me ghost stories want to do? Cultivating to become a celestial is too hard, I want to go back to Earth!"