There's Something Wrong with the Protagonist (Through the Book)

After Lin Xuanze died unexpectedly, he was taken to a book by the system, and he would replace the protagonist in the book and complete the miserable life of HE after being physically and mentally abused as planned. Unexpectedly, he discovered that the original owner's soul was still there just after passing through. After rejecting the system's proposal to destroy the original owner's soul, Lin Xuanze had to share the same body with the original owner in embarrassment. Fortunately, this is the world of cultivating immortals. He only needs to complete the task and train himself to have a body before the original owner tries to destroy him. Later, Lin Xuanze discovered that the original owner not only changed his mind about killing him, but was also more active in refining his body than he was. Why is that? Gu Shiyuan had a rough life. His family was massacred when he was young, and he was displaced. When he was young, he struggled to become a disciple, but found that the master only regarded him as a medicine, only waiting to be harvested when it was ripe. The only sincere friend he had as an adult coveted him, took away his fortune and imprisoned him for several years. In the end, he was forced into the devil's way, killed all those who betrayed him in the world, was yelled and beaten by all the decent people in the world, and was besieged and killed on the top of Chifeng. Then, he returned to the day when he succeeded in becoming a disciple. The only difference is that there is an extra soul in my mind. First acquaintance—— Gu Shiyuan: I want him to die. Lin Xuanze: Boss, please forgive me. After a while—— Gu Shiyuan: It's okay not to kill him. Lin Xuanze: Leave the boss quickly. Later—— Gu Shiyuan: This is the person I will spend the rest of my life with. Lin Xuanze: Why is the boss more active than me? Intention: You can see the light when you raise your head.