I Fabricated the Techniques, but my disciple really mastered them? - Chapter 772 - 406 Ant Tricks, Turn to Ashes and Oblivion

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

When Fang Zheng opened his eyes, he was surprised to find himself reborn in a fantasy world of magic, dragons, knights, and princesses. Not only that, but even the game system that Fang Zheng had designed before also followed him into this world. Then, his next step would be to traverse thousands of plains, gain endless strength, become a brave hero, defeat the devil, marry the princess, reach the apex in life… wait, wait, wait, before all that, why was he reborn as someone who everyone called a cultist?

Zhuang Feng is in his last year of high school, and he’s just moved to the city. He lives with his good-for-nothing cousin, who’s always on business trips falling for get-rich-quick scams, and his Saozi (sister-in-law), who tries to make his life miserable as much as possible. There’s one upside, though; she. is. freaking. hot. But one day, he found a piece of her underwear in the bathroom…. And unfolded a series of events that will turn his life upside down.

- Description from Novelupdates