The Protagonist Lost His Character After I Died

[Main story complete! Bonus chapters may appear at random!] Huai Si is a supporting character in an apocalypse novel about the protagonist's rise to power. The protagonist is a nobody everyone looks down on, while Huai Si is a young master from a prestigious family, long separated from his kin and filled with compassion for all. He becomes sworn brothers with the protagonist and protects him. In the first third of the story, he sacrifices himself to save the protagonist, blocking a horde of mutated zombies. His death lets the protagonist assume his identity and advance further. He thought that once he completed his sacrifice, he would have earned his reward and moved on. Strangely, his soul remained within three meters of his body. He watched the protagonist clutch his not-quite-dead body and weep, even planting a kiss on his lips, where tears mingled with the moisture. What... What was going on? This wasn't right! In the original story, the protagonist was supposed to wait until he was definitely dead, then bury him despite his grief, so the zombies wouldn't devour him. Instead, the protagonist carried his "corpse" away from the survivors' settlement and hid with him in an abandoned house where they used to rest. He left everyone behind and gave up the power he had already established. Huai Si reassured himself. It was fine. The protagonist was a loyal, devoted person, and Huai Si was his brother, someone he had risked his life for. That was, until he saw the protagonist refusing to let go of the fingers of his "corpse," stroking the deathly pale face with a diseased intensity. His gaze was full of infatuation, almost obsessive, as he used Huai Si's cold fingers to comfort himself and whispered his name. "Huai Si..." For three whole months, the protagonist lived alone with his "corpse" day and night, nearly going mad as he obsessively tried to keep Huai Si there in ways Huai Si couldn't understand. Huai Si fell silent. Maybe it would be better to just die. Oh, right. He was already dead. Suddenly, the world spun around him. He opened his eyes and met the protagonist's delighted gaze. The protagonist was performing his daily routine, carefully wiping down Huai Si's skin. Even a slight movement made Huai Si feel how tenderly he was being cared for. Huai Si: "..." Well done, author. You actually revised the story. Because the author revised the story, Huai Si returned to his body. Now, as a supporting character who had failed to die, he had become a mutated zombie. The protagonist was supposed to kill him in agony, allowing his spirit and character to ascend to a higher level. "Hah..." Huai Si opened his mouth and let out a zombie's growl, then lunged at the protagonist to bite him! "Huai Si..." The protagonist murmured his name, clamped a hand around the back of his head, and gripped his jaw with the other. Ignoring his zombie form, he kissed him deeply and possessively, taking everything from him. The tip of his tongue grazed the sharp fangs that had grown from Huai Si's mutation, drawing tiny beads of blood. Huai Si: "Mmph..." But the hand that had been resisting suddenly hooked around the protagonist's neck! He tasted human blood. A zombie's instincts made it impossible to resist, so he could only give in to them. The protagonist narrowed his eyes and deliberately dragged his tongue hard across Huai Si's fangs, cutting it open! Blood surged out and streamed from the corners of their mouths... Huai Si clung to him tighter and tighter, his eyes turning completely red as the thick taste of blood filled their mouths and he lost himself in it. "Huai Si... Now you can't leave me..." Couple: A zombie bottom who wants to follow the plot but loves humans x a top so obsessed he's gone mad and doesn't care about humanity [Reader's Guide] 1. After the bottom's soul leaves his body, it isn't a corpse. It still has warmth, though very little, as if the soul had simply left the body. 2. This may not be a feel-good story (though I think it is). Please don't flame me if it's not to your taste. 3. In a sense, both the top and bottom are lunatics. 4. Their mental states are completely unhinged. Theme: Only love is eternal.