Online Game: I Possess a Monster Merging Simulator! - Chapter 33

When Li Xianyu was 20 years old, he received his father’s inheritance, an 18-year-old great-grandmother who was incredibly beautiful.

Li Xianyu: “Great-Grandma, why are you so young?”

Great-Grandma: “That’s because I died when I was 18 years old.”

A skilled thief gets a system in an Alternate Wizarding World. The system seems useless in the beginning since he hasn’t unlocked any features. But…

[The very first feature of the System has been unlocked.]

[Congratulations. You’ve unlocked the class feature. Due to your existing skills and experience, you have gained the Special Class "Arcane Thief" as your starting class. There’s nothing an Arcane Thief can’t steal. The more you steal, the more your Class will progress.]

[The fields of expertise include:

— Stealth Magic
— Wards
— Traps
— Enchantment
— Pickpocketing
— Knife/Short-Sword Wielding]

Wait…this is just the first feature?

The scum’s or villain’s long road of transformation was tentatively set to the world:
The abandonment of the educated youth’s wife (Completed)
The hidden marriage of the scum film emperor (Completed)
The best brother in the world (Completed)
The Phoenix male who destroy the bridge after crossing the river (Completed)
The treasonous general (Completed)
I’m an honest man (Completed)
To become the top scorer in the School of Agriculture (Completed)
The soft rice man’s self-cultivation (Completed)
The whole world is reborn (Completed)
I want to survive on a desert island (Completed)
The stallion male who has seized the opportunity (Completed)
The perverted self-salvation (Completed)
The spring of the loafer (Completed)
The misplaced life (Completed)
The miser career (Completed)
The ghost is out of feeling (Completed)
The Queen’s favorite husband (Completed)
The vicious girl with her godfather (Completed)
I want to be a good person (Completed)
I does not tear up the family (Completed)
The perverted common plant (Completed)
The Mary Sue’s men (Completed)
Every time I was reborn, someone wants to kill me (Completed)
The old people’s counterattack path (Completed)
The global evolution (Completed)
When I became a net red (Completed)
For you, good person (Completed)
His heart had white moonlight (Completed)

- 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.