The Extreme Alchemist of the Mighty Cauldron - Chapter 15 - : Apprentice?

An old MMORPG called Live Dungeon. Before the service was terminated, Kyotani Tsutomu made full use of 5 notebook PCs to clear the game and was invited to a different world. And then, Tsutomu was speechless when he saw a live relay of a dungeon capture in the different world. They bulldozed through without any thought of strategy. The misfortune of getting the healer position. Tsutomu reinstated the White Mage that had always been his favorite in games and aimed to conquer the dungeon to find the key to his escape from the different world.

I am Ye Qing. Lucky I found a [Monster Factory] application.

Ye Xiao was a superior cultivator in his previous life. The three factions of the realm kill millions of people every time they attempt to seize cultivation resources. Wealthy towns turn to wastelands in just a single night. They cover up their crime with an assertion that the towns were suffering from pestilence and disasters.

They forcibly hold all the resources for cultivation, monopolize all valuable practice materials, and keep outsiders from cultivating so that only their three factions could cultivate in the realm. Ye Xiao declared war against the three factions in retaliation for their actions. He fought alone and ended up dying in vain. However, he is reborn into the mortal body of a 16-year-old boy. He will use the powers he cultivated in his last life and slaughter his way back into the Realm. The story begins!

- Description from Novelupdates

Xiao Ran transmigrated to a fantasy world. As a dungeon guard in the Celestial Dungeon, with a special floor called the Purgatory meant for powerful demons and martial arts experts, he faced a huge challenge from the start. The Eldest Princess acquired a forbidden martial arts technique and was banished to the Purgatory. However, no one was powerful enough to restrain her. All the dungeon guards were defeated. Xiao Ran stepped up and declared, “Your Highness, it’s better for you to behave yourself on my territory” and effortlessly subdued the Eldest Princess.

He progressed from imprisoning the Eldest Princess to delivering the Great Xia Kingdom from the evil clutches of various demons and evil martial arts experts.

…

Xiao Ran was the mastermind behind the scenes.