(Demon Slayer) Kurokawa Says He Isn't Human

Heichuan is a cat, and a cat who holds a grudge. During the Heian era, black cats were considered auspicious. It was said they could ward off evil, bring good luck, and drive away misfortune and wicked spirits. The Heichuan family had a cat like that, only this one was more lively, spirited, and understanding of people. But in the end, the cat was left to wander outside, became a demon, and unilaterally declared a grudge against Kibutsuji Muzan. During the Taisho era, black cats were seen as messengers of misfortune. At that time, Heichuan, who had been in seclusion for a thousand years and had finally gained the ability to take human form, needing only an opportunity to slay demons, emerged from seclusion... I'm new at this, and my writing is poor. I'm a character-death-reversal machine. Croc, kill me. OOC warning: I'm afraid I'll write the characters out of character, but without the tragic characters, the story wouldn't be complete. Pairing undecided. (The first four chapters aren't very good. They're basically background for the protagonist and have nothing to do with the plot's characters. They're entirely original, so you can skip them.) Theme: Good and evil are always repaid in the end