Fate Online: Shadow - Chapter 1: I Am Back!

This is a tale that distorts the scenario of an otome game.An orphan girl named Alicia is attacked by a woman trying to steal her body to become the “heroine”. From the fragmentary knowledge she acquires, Alicia learns that this world is the stage of an “otome game” in a “world of sword and magic”.Having learned the truth from the knowledge she obtained, the immature Alicia dismisses the otome game as “nonsense” and runs away from the orphanage to escape the fate of the “heroine”.A villainess aims to take her life. A fake heroine appears. Alicia trains herself using the fragmentary knowledge she has gained in order to survive, growing into the “Strongest Assassin” that is feared by both the Thieves’ Guild and the Assassins’ Guild.

# RELAXED # INFINITEDivine-grade Decomposition and Reconstruction System: This allows the user to decompose any object and reconstruct them.…A scraped car? I’ll just disassemble it and make it into a brand new expensive luxury car!A bunch of small diamonds? I’ll just turn them into a 10-carat giant diamond!An old phone? I’ll just make a futuristic phone that won’t appear for another 70 years!”What? Did I get sick? Simple! I’ll just gather a bunch of drugs, decompose them, and make a super medicine out of them!…A few years later, Augmented Reality, the Automated Electronic Management System, air-powered vehicles, humanity's first moon base, and other cutting-edge technologies were all created by a man who was once known as Dumb Lin.

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

- Description from Novelupdates

Lin Chen was persecuted by his childhood sweetheart and accidentally obtained an ancient legacy. From then on, he embarked on a path against the heavens!“I am a sovereign! Those who insult me will be killed, those who obstruct me will die!”