Toaru Majutsu no Index: New Testament - Volume 9, Chapter 7: “A Normal High School Boy”. Black_or_White.

Su Qin crosses into a world where martial artists run rampant, where Buddhist monks from the Yuan Dynasty dominate the world. Jiuyang’s successor’s fist conquered the mountains and rivers, and Xiao Li’s flying knife smashed through the void.

Because Su Qin had no martial arts qualifications, he could only become a sweeping monk in the Shaolin Temple. At this time, the ‘Sign In System’ was activated.

Sign In in front of Buddha’s Golden Body, get [Buddha’s Palm].

Sign In in front of the Arhat Hall, get [Invincible Vajra Divine Art].

Sign in at the back mountain of Shaolin Temple, get [Golden Demon Body].

The Shaolin Temple was riddled with treasures, and you can sign in everywhere.

Su Qin decided that he would never leave the mountain without Signing In to everything in the Shaolin Temple. And so, he Signed In the Shaolin Temple for twenty whole years!

Twenty years later, the Shaolin Temple got mixed in the battle between the Righteous and Evil.

The Demons were fierce and powerful, they blatantly invaded the Shaolin Temple and were pushing forth with great force, but that is until they met Su Qin who was sweeping the floor…

It was supposed to be a perfect deal in which both parties got what they needed. However, after the child was born, he tore up the agreement with discontent and told her, “Who said that we’d only have one child? I want twins! Twin brother and sister! You’ll continue giving birth to more children until you bore me a pair of twins!”

She was born into a powerful family of the nobility, a blue-blooded aristocrat as capable as any man. He rose from humble origins up the military ranks, an iron-blooded knight with high ambitions. A transaction for power severed her from her childhood sweetheart. A tardy encounter was the beginning of his and her vow to meet life and death under heaven, standing shoulder to shoulder.

Political intrigue, dynastic succession struggles. He trampled through it all in the toil of becoming emperor.

Old enmities became new disputes, concerning life and death of entire families. She entered once more into the palace, changing the entire political climate of their world.

Meeting once again, they had become strangers. The peach blossom were all fallen, no more than a golden age grown cold.

- Description from Novelupdates

Instead of struggling meaninglessly, he acknowledged his place.