After the main character is transmigrated, he follows the system in his first life and takes the main character as his disciple, but he is killed by the main character in the end. After his rebirth, he takes the villain as his disciple.

This kind of novel theme was more common. You could search for some classic novels such as " Demonic Ancestor " and " Dream Chasing Entertainment Circle ", which had similar plots of the protagonist taking in villains as disciples after rebirth. The following is an article that might meet your requirements: " Reborn Villain Self-Rescue " The main character was a reborn person who had transmigrated to a certain novel world. His first life was a small invisible character in the original novel that was targeted by the main character. The main character was a powerful and evil character with a very high status in the novel. At the end of the first life, the protagonist realized that he could use the power of the system to start over again, so he chose to follow the system's original route and become a powerful villain. The protagonist learned many skills and knowledge in the system and became a very powerful villain. After becoming the villain, the protagonist began to take revenge on the protagonist. He planned to weaken the protagonist's position and strength through various means, and finally defeat him and replace him. However, the main character was not easy to deal with. He also had his own plans and conspiracies. In a fierce battle, the protagonist was finally killed by the protagonist. However, his death was not over. After the protagonist was reborn, he realized that the existence of the protagonist was a great threat to him, so he decided to take the protagonist as a disciple and train him to become a stronger villain. The main character was not to be outdone. He began to study hard and grow, hoping to obtain more strength and skills in the system. In the master-disciple relationship between the protagonist and the protagonist, feelings gradually developed between the two. However, their relationship wasn't looked up to by others because the protagonist was an evil character. His actions were condemned and opposed by many people. In a series of complicated plots and tests, the protagonist suffered and the protagonist attacked. Finally, they completed a plan together, realized their goals, and also gained a precious friendship.