The Female Supporting Character Just Wants To Live A Good Life - Chapter 75.2: Memories Part 2

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

Luke is a half-beast who grew up in the twisty streets of a large city called Oukiwa. Abandoned by his parents as a child, he soon had to learn the arts of thievery to survive.

Even on the fringes of a super-powered society, he has followed a single rule all his life: never get involved with the Adventurers.

However, this rule is broken when his gang begins to hatch a plan to rob the most powerful family in town.

And so begins the chronicles of Luke Lange, a thief with no ancestors who in the future becomes one of the strongest men in history, with powers that are rivaling even the gods.