Toaru Majutsu no Index SS - Volume 2, Chapter 15: Art is Divided between Geniuses and Eccentrics. The Fourth Friday of September.

People in the World of Naruto: Drinking Makes You Stronger
 Author: Half a Piece of OrangeYouyu, a man who found himself transported into the Naruto world, awakened a rather unusual system:The more he drinks, the stronger he becomes!• Raikage: “What?! I have the strongest defense—wait, why did Youyu just slice through me while drinking?!”• Hiruzen Sarutobi: “That guy’s a monster. I’ve never seen him train, only drink... yet he still cut me down in an instant.”• Madara Uchiha: “Dancing? Tch. That drunk bastard swayed his way over and chopped me up!”• Obito Uchiha: “Damn it! Even space-time jutsu can’t stop that drunk maniac!”Youyu: “My hobbies? Drinking... and cutting people down.”

The end of the world is coming, the world has undergone great changes, and everything has changed. Plants, animals, and even insects, as long as there are living things, have mutated.
Become more powerful, and even evolved supernatural abilities, such as chickens and ducks that can fly to the sky, such as cats and dogs that can breathe fire.
But only humans, without any obvious changes, seem to have fallen from the top of the food chain to the bottom of the food chain overnight.
Any creature that can open its mouth to eat can treat humans as food.
But fortunately, this world has not completely killed humans. Gradually, humans discovered that they had the ability to cultivate compatibility with other creatures.
As long as it has a high degree of compatibility with some powerful mutant creatures, it can be used for its own use to achieve the purpose of protecting itself.
Fang He is a person who is very compatible with mutant animals, but it is also because of his ability that he has changed from the strongest to the stupidest.
Fang He, who was reborn, said, “Hmph, this time…”

- Description from novelbuddy

【Ding! Beast Mode system binding successful!】【“Ding! Main Mission: Master of the House; As an upstart son-in-law, you should turn the tables and show your mother-in-law's family what it means to invite a wolf into the house.”】In a daze, an interface floated in front of Xu Bin's computer, with multiple side quests displayed. These included a voluptuous and sexy mother-in-law, a tall and seductive sister-in-law, a loli sister-in-law with massive tits, and several hidden side quests that were not yet visible.Tags: Harem, Mother-Daughter, Erotic Novel, Sister in laws, MILF, Housewife, Loli , Yandere, Lesbian