Harry Potter: Ero World - Chapter 100: Onto his trail!

Zhou Yu, a reclusive otaku, who did not like to go out of his house, was one day forced out of his house by a series of unexpected events.

- Description from Novelupdates

After blacking out at a class reunion, Li Yuan awakens in a brutal world reminiscent of ancient China. Famines rage, human life is cheap, and the specter of war looms at every corner. Worse still, the eerie rumors of monsters lurking deep in the forests and things that go bump in the night prove all too real.Now scraping by as a humble hunter in a remote village, Li Yuan must also watch over a woman entrusted to his care. Although he’s blessed with a mysterious status window, he’s still just a leaf on the wind—easily blown astray by the sweeping storms of change. Join him as he struggles to navigate political upheavals and unforeseen perils, striving to forge his own destiny as history unfolds around him.Official: Li Yuan crosses over into a martial world where demons and ghosts lie dormant, becoming an ordinary hunter struggling to survive. It’s only after he takes a wife that he discovers a status window. As the stars shift and ages pass, though seas dry and lands change, he remains steadfast and unchanging.

I became a staff officer of an empire whose defeat was certain.The only way to escape from the empire with an 8-year mandatory service was through dishonorable discharge.But then…“You can be glad, Lieutenant. Thanks to your accurate instinct, our military could prevent damage in advance.”The more I struggled to be discharged, the higher my performance evaluation became.

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.