Toaru Majutsu no Index - Volume 15, Epilogue: The Victory Prize for Those who Survived. Nano_Size_Data.

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of powerful enemies by depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest!

Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.

We are born free; yet, why do the deities and Buddhas claim supremacy!Bodhisattva, Buddha, Deity? ... I shall wipe out all your Divine Souls!If the heavens obstruct me, I will shatter these heavens; if the earth obstructs me, I will crush this earth!Tathagata, today you must return to me—five hundred years!...

This novel is also known as Master Fu's Mysterious Darling Wife

She is the The Young Miss of Military family Shen, her face is peerless, her temperament is cold, and she is her family’s treasure, but isn’t accepted as one’s child by her mother;

He is The Sole Heir to the top giant Fu Family, his power is unparalleled, indifferent high-born, the captain of the mysterious military force, and the youngest commander-in-chief.

Because of her grandmother’s wishes, she married him at lightning speed. She thought that it was a marriage that she needed, but she didn’t expect to be greeted with his extreme pampering.

- Description from Novelupdates

After everything that Zaroth had was stolen from him, he decided to live solely for his desires, morals be damned!Close to his death, he resurrects and tames a mythical dragon, who turns out to be a breathtaking woman.Learning that in order to explore her body, he must grow stronger so he doesn’t die during the act, Zaroth sets a clear goal for himself: to get stronger.“But I’m curious about something.”“Hm? What is it?” Luna asked, raising an eyebrow.“You said you judged me. How did you do that? Why was I worthy?”Luna’s smile darkened, her eyes glowing with a dangerous intensity.“Despite knowing you would die, you didn’t pray to the gods. On the contrary, you declared that you would kill every single one of them like the dogs they are. In my life, you’re the only one who’s ever made such a declaration, which is why I couldn’t leave you behind—someone who dares to share my dream.”