Chronicles of Primordial Wars - Chapter 819 - Enslave me?

One day, I woke up only find out that I’d become a Demon Lord, an individual responsible for protecting a dungeon. The world I’d been spirited away to was one filled with violence. Gigantic monsters wandered through it and competed with each other each and every day for the right to survive. I had no choice but to strengthen my dungeon’s defenses in hopes of living another day—or at least that was what I’d thought. For some odd reason, I instead ended up spending my days in relaxation and bliss.

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!”

- Description from Novelupdates

Yu Sui and Shi Luo met each other when they were much younger. One was a pro-gamer, a widely-renowned, best of the best, in-game medic. The other was an e-sports newcomer who was just starting out. The two originally played for the same team, during which their relationship became increasingly deep.

A side story series featuring the girls of Kyoukai Senjou no Horizon.