Stone Mage: Revenge of the Villain System - Chapter 43 An ’Accident’

Shenwu mainland, Yangwu worships God. A generation of Tianjiao, Wu Sheng was born again. Too really water, refining the body. Boxing the world, feet and arrogance. The celestial emperor, the law is empty. “Dare to despise the brothers, all killed!” “The woman who dares to move the brother, has been sleeping!” “Brother is just a myth, no one!” – from the quotations of the Emperor Lingfeng. The Supreme Demon is a very popular fantasy fantasy type written by the author, and tells the vivid story of the Supreme Devil.

- Description from zhuishubox (translated)

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.

- Description from Novelupdates

Failing in his job hunting, Sanada Kyouichirou was hopeless in this society. When kyouichirou had thrown himself towards the bottom of a cliff. When he woke up his body had returned towards when he was in fifth grade of elementary school. He did not want to have any regrets in this life so he had decided on building up an harem in this second life.

The elder sister that he admired, a senior and president of the student council at a school for rich young girls, a strong minded upper classman at school. The poison fang of Kyouichirou who had pretended to be a innocent child attacks those girls.

In a romance novel called “The Secret Lovers of the Academy” the male lead would often torment his fiancée–but wait, why did she cross into this world to become his fiancée, the villainess, instead of the heroine?