Isekai Maou to Shoukan Shoujo Dorei Majutsu - Volume 12 Chapter 4 part1

Upon meeting the girl who would become her adopted younger sister, the duke’s daughter Christina regained memories of her previous life. Through those memories, she learned that her new sister, Mishuli, was the heroine of a certain story. And though the story depicted a Christina who abused her sister, the real Christina turned into a siscon who spoiled Mishuli to no end.

Ye Xuan was transmigrated to the Qingyun Sect and became the youngest elder. At the same time, he had also received the 10000x Disciple Cashback System.

From a young maid to a previous noble lady and the demonic empress, he accepted all of them as his disciples.

No matter what he gifted and taught his disciples, he would receive the same thing back in 10000 folds.

“Ding! You have given your disciple a low-grade Nirvana Pill. You have been rewarded with the Heaven Path Pill.”

“Ding! You have given your disciple the Sky Blazing Sword. You have been rewarded with the ancient divine sword, God Slayer.”

“Ding! Your disciple’s cultivation has increased by a year. You have been rewarded with 10000 years worth of cultivation.”

Ye Xuan continued to accept more disciples until one day, one of his disciples, the empress, exposed his identity.

It was then that the world learned of a person who was the strongest.

A cultivation story about how a declining sect is restored by a narcissist, a troublemaker, a meanie, an idiot, and a wimpy kid.

- Description from Novelupdates

The first time they met they had battled fiercely, just for a mere bunch of herbs. She needed it to save people, and he wanted to use it to save his own life.

“Let go of it, or you will die.” The man’s violet eyes were cold and sinister as he said in a low voice.

She held on tightly to the base of the herb and pulled its roots right out of the ground, before she turned her eyes back with a crafty smile. “It’s mine now. Snatch it from me if you can.”

When they met several years later they were no longer on opposing sides in hostility. In order to repay the debt for having stolen the herb back then, she went on to miraculously cure his body’s condition, relieving him of the inhumane torment that wrecked at his body day and night. He was amazed by the godly skills in Medicine she possessed and his heart went on to fall irrecoverably head over heels in love.

- Description from novelupdates