Harem Tales of a Reincarnated Elf Prince - Volume 1 Chapter 4

The little princess of the Huo family, one of the wealthiest families, was mistakenly switched out nineteen years ago! The fake heiress is well-educated, talented, and doted on, while the real heiress is an uncontrollable girl who loves to fight, has a strange personality, and had dropped out of school very early…

One of the top expert killers, tired of endless assassinations and having survived a cruel and suppressed life, decided to escape the world’s strictest assassin organization.

Hiding in the Cold Palace and eventually becoming a Boss of Sorts. Li Mu was transported to a fantastical world and became a measly eunuch of the State of Xia. Despite having initially thought that his life would be a miserable one, he had unexpectedly acquired a check-in system.

A master assassin transmigrates into an interstellar era.

Other players were responsible for competing in the e-sports arena, while he was responsible for stringing up and beating up the other players.

His sword was hidden during the peak of day, and he was a gentleman who arrived in a flash of light;
As a vanguard of the eternal night, he was the variable between life and death in the world.

“As you know, the Star League’s difficulty levels are arranged in this way:
Paradise < Simple < Normal < Difficult < Nightmare < Hell < [Tyron Odin]”

- Description from Novelupdates