Toaru Majutsu no Index: Genesis Testament - Volume 4, Afterword

A novel revolving around being transported to another world with an op system. The mc spends his day chasing skirts and doing missions to level up. A standard journey to the top with lots of girls from various animes and games with a twist of that gaming feel (hunting mobs, doing missions).

- Description from novelupdates

In fact, Ling Yun was the son of a wealthy businessman. But one day, his mother finds out that her husband is having an affair with his secretary. And after that she decided to divorce her husband, but at that time she did not realize that she was pregnant with Ling Yun.

After learning about her pregnancy, she decided to move to another city. And since then, their lives have been up and down. Because of the economic crush, and also his mother's health was getting worse.

He decided to take the 'Dark' path, which led him to near death. But just as Ling Yun was nearing his end, he heard a little girl's voice asking him.

“Do you want to live?”

As soon as she fell into the world of beastmen, a leopard forcibly took her back to his home. Indeed, Bai Qingqing is at a complete and utter loss. The males in this world are all handsome beyond compare, while the women are all so horrid that even the gods shudder at their sight. As a first-rate girl from the modern world (she’s also a quarter Russian), Bai Qingqing finds herself sitting at the center of a harem filled with beautiful men — at the very peak of existence.

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist “I am the real summon master.” Takuma gets slave-turning magic used for summoned beasts cast on him by the girls –