MTL - Douluo: Star Officials Challenge, Everyone is Better Than Tang San - Chapter 575

In the King’s game, the [King]’s order is absolute and has the power to create rules. As the owner of a special physique, Gu Huai was selected by the system to participate in the game. “Win the game and become the [King], and you can obtain whatever it is you desire.”

- Description from Novelupdates

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

This novel is also known as Transcendental Mechanic

What do you do when you wake up and find yourself inside the very game that you love?

What do you do when you realize you that you have not only become an NPC – you have even been thrown back in time to before the game even launched!

What will happen when our protagonist’s two realities coincide?

Han Xiao was a professional power leveler before his transmigration. Using his past life’s knowledge, Han Xiao sweeps through the universe as he prepares for the arrival of the players. This is definitely not your typical transmigration novel.

- Description from novelupdates