Runeblade - Chapter 4 : The Grove

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

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.

One day, the whole world gamified in the eyes of Su Mo.Not only could he use his lifespan to draw cards, but he could also see the hidden attributes of every item in life.As such, when he looked at the hanging lamp above him, he saw:[Item: An old hanging lamp][Hint: It will drop after one minute and seven seconds.]When he looked at his right arm, he saw:[Item: The right arm of a young man][Hint: The grip strength of his right arm is 3% stronger than that of his left arm due to continuous training.]When he looked at the ginseng on the table, he saw:[Item: A stalk of wild ginseng][Hint: It is tinted with a layer of source power. Consuming it could make you feel energized.]…Excited, Su Mo rushed to meet his girlfriend, who was a school beauty and had just agreed to date him.He then saw a bright red HP bar on top of her head.[Item: A very thirsty fox demon][Hint: You might not be able to put up a fight against her.]

One night she gets drunk and mistakes the most well-known Mafia boss for a Host* and intends to sleep with him.