One Piece: Alucard the Immortal - Chapter 31: The Two Gun Wielders

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.

When waking up, Jiang Tian found out that it was not too late.

In his previous life, Jiang Tian was a member of Jiang family in Jinling. He suffered a disgrace that was his fiancee broke off the pledge of marriage, so he had to marry into the Zhao family. Although Zhao Xueqing, his wife was the first beauty in Hangzhou, he always beat and scolded her. A few years later, he went through a family upheaval, and his loved ones died one after another. With despair, guilt and hatred, Jiang Tian jumped from a cliff. But he did not die. Instead, he started a cultivation journey for as long as ten thousand years in another space.

He became the supreme god, but he died in the process of opening up the universe. With the regret for his parents and the guilt for Zhao Xueqing, Jiang Tian, who retained several thousand years of memory, swore that he would never let his loved one suffer any grievances and injuries this time!

- Description from Novelupdates

Oscar, a destitute young boy, died in a tragic accident and was reborn in the forgotten realm. As a member of the lowly Birch tribe, his solace comes from the fragments of a guardian's spirit, residing in his soul. After the decimation of his family in the hands of a powerful race known as the dreads, he embarked on the part of revenge, leading him to the path of transcendence.

Kim Bo Myung, after graduating from high school years ago was living a below average life as an employee of an entertainment agencies PR department.After getting run over he opened his eyes to see that he was back in the past in the body of a member of an idol group?!He gets a chance to regain his lost dreams and write a new legend in the entertainment world and also get revenge !