MTL - Rebirth of the Super Thief - Chapter 346 : Magma Zone

Caution: This novel contains R18 content. Doomsday had arrived overnight. Zombies roamed every corner and humanity had suffered a massive setback.

Collapsed without warning, and upon awakening, he found himself back in his childhood.He thought it was a blessing from above, but unexpectedly, tumultuous changes ensued, shrouded in mystery...

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

A loner boy, who’s always loved escaping into his RPG world, suddenly finds himself living as one of his game characters. But instead of becoming his favored fighter, he’s in the body of his second avatar—a support mage! Though he’s used to playing both roles, being the mage in real life is a whole new challenge. Now he must rely on his knowledge and skills to navigate this unfamiliar reality and survive as the game's “support.”