MTL - Lord of the Secret Art! - Chapter 2 stolen body

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.

He is the ruler of the mercenary realm, an overlord that gives headaches to the leaders of any country! For the sake of his friends, he’s willing to sacrifice himself; for the sake of his family, he does not hesitate to spill blood! He is a dragon, one that soars above even the highest of heavens. He’s a power that advances triumphantly through unstable situations, stirring up both the winds and the waters.

What do you do when your brother dies because of some entitled assholes? You go undercover.My real name? Clare. But at school, I’m Clause—just another guy blending in. Disguised. Watching. Yes, a boy. No, it's not an all-boys school—I'm just deep undercover, hunting down the bastard responsible for my brother’s suicide. Nobody—and I mean nobody—messes with my precious brother and gets away with it. They better pray I never find them, because when I do? Death will be a mercy, and trust me—I don’t do mercy.And as for the egotistical Alpha and the narcissistic Vampire Prince? They can go fuck themselves. I don’t do mates, I don’t do claiming, and I sure as hell don’t do them.

Blue Star has entered the extraordinary era, everything is evolving, and monsters are rampant.

Humans awaken their star souls in evolution to fight against raging monsters.

Zhou Xuan, who was doing odd jobs in the Demon Town Tower, accidentally awakened to an unscientific sign-in system.

Sign in on the ancient desolate beast and gain the power of the wild. Sign in on the weed spirit, and the star soul evolves into the nine-leaf sword grass.

The thousand-year black turtle, the ten thousand-year sea king, the immortal true phoenix, and the sky-swallowing dragon have all become the targets of his registration.

There are countless monsters in the Demon Suppressing Tower, Zhou Xuan signed in silently, and if he was not careful, he would be invincible.

- Description from novelbuddy