Douluo Dalu 2: The True God King - Chapter 316: [DD2]:

Qin Tian accidentally transmigrated into a sickly body, a body with broken Dantian that was unable to practice Qigong, in another world. Fortunately, God had mercy on him by giving him a level up system. Useless? That was him in the past. Not worrying about practicing Qigong, he was now able to kill Monsters to level up. Easy! Level up when killing Monsters; level up when killing people. An unbeatable sovereign of the clan in the eyes of other people, but in his eyes, he is a glittering big BOSS.

Humanity’s first 8th Class Mage.

Betrayed, he traveled back 30 years into the past.

The story follows Ian Page, archmage and the first man to break through the 6th class, then through the 7th and become the most powerful mage, an 8th class mage.

After a lifetime of war and killing, the continent was finally unified thanks to his efforts. Now, old, his wish is to live the rest of his life in peace and try to find salvation for all the blood he spilled. However, his old friend, maddened by paranoia, couldn’t tolerate someone so powerful, so he betrayed Ian and killed him.

In his last breath, he cast a time magic that allowed him to travel back to when he was a young boy. With all the knowledge he previously had, he decided to do things better so he could end with less regrets.

Because of boredom, Xu Jinyi entered a game. In this game called “Different Worlds”, he needed to play some cannon fodder or villain to live a happy new life.

Xu Jinyi worked hard to finish the game, and finally realized that this game was actually a scam created by Zhao Chengli specifically for him.

- Description from Novelupdates