MTL - The Day of the Draw at Hogwarts - Chapter 6 london holiday

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.

Amidst a disaster, an orphan contracts a sickness.

What’s worse than finding out you’re that Louis XIV when you’re a baby?

Of course there is, for example, it’s still a magic version.

- Description from novelbuddy

After dying from betrayal, Thomas reincarnates as Jolthar Kaelzhar, the neglected son of a powerful clan, just after his brothers kill him. With Jolthar's memories and the blessing of Qalena, Thomas vows to rise from his lowly position and claim power in his new life.