Bro, I'm not an Undead! - Chapter 1444 : Skullius’ Conclusion (1)

A lecherous army special task force soldier from 21st-century Hong Kong is selected to travel back in time, choosing to go to the Chinese Warring States Period. Unfortunately, the time machine runs into an error during the experiment. With no foreseeable way to return to the present, he must use his combat skills and knowledge of history to thrive in his new life in the year 251 BC.

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

“21 days. 7 hundred million won. 29 strangers. One unforgettable man.” Yoon Ji-won never planned to become a substitute driver. He never planned to be locked inside a building for 21 days with 29 dangerously attractive men. And he definitely didn’t plan to have his world turned upside down by a smooth-talking younger guy who won’t leave him alone. After a mysterious interview, Ji-won is thrown into a secretive, high-stakes project with an offer too tempting to refuse. The rules? Obey. Stay. Survive. But when he meets “Number Three,” everything starts to unravel. Cold stares. Lingering touches. A spark that turns into a fire he can't put out. Is it destiny? Or just another trap? For readers who crave intense power dynamics, isolated tension, and twisted attraction wrapped in a sleek, modern BL thriller.