Seventeen Again: The Sweet Life with My Family - Chapter 602 - : Where Is She

After transmigrating into a beast world, Rong Mingshi discovered that the people of this world experienced widespread mania. For example, when their emotions were abnormally agitated, they would become destructive beasts. If their emotions were abnormally low, they would shrink into their young beast form.

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

Summary Version 1:

The mysterious boy Ling Chen is saved by a little girl as he lay on the street dying. Years later, he strikes a deal to save this savior-turned sister and enters the virtual world. In a future Earth where advanced warfare has forced nations to settle issues virtually or else suffer the consequences, Ling Chen bursts into the scene and goes from unknown to legend. Yet all is not as it seems, for Ling Chen has a dark past, and there is a greater mystery at hand behind this virtual world.

Summary Version 2:

To save his terminally ill little sister, Ling Chen enters the newly released virtual game world and joins a small gaming studio comprising entirely of women. From now on walking upon his path towards the pinnacle. An ancient, evil item almost forgotten by history, the “Lunar Scourge” helps forge his unsurpassable legend, and causes him to unknowingly step upon a path that is destined to be punished by the heavens, the way of the shura.

The Queen of the elves wants to bear his child, the vatican’s saintess is his maid and the empire’s princess wants to elope with him.

But his only concern was his delusion of taking down the creator of the world!

- Description from Novelupdates