He didn't understand people well in his life. In his short life, he didn't realize until the end that what was really good for him was what he had been avoiding and hating. The paranoia and deep affection in that person's eyes had always been for him alone. He once thought it was a nightmare, but only at the end of his life did he realize that he was so lucky to spend his whole life.
At this point, the resentment is so high that it will not end well. Burning his body with karma, he walked through the eighteen levels of hell one by one, his hands stained with blood, controlling his destiny, changing time to look back, and reversing time and space.
If he goes back to his previous life, even if he burns his body in blood and transforms into a Shura, he will still be entangled with that person for the rest of his life.
I have been in this world for twenty simple years, and have been waiting for thousands of years in hell, just to meet you again. Can you please let me stay, and devote myself to you in this lifetime?