Being a demon slayer, not the best. But you need revenge. A demon killed your loved ones and you became a demon slayer. One night, you come across a girl who has a muzzle in her mouth with a pink kimono and a black haori over it. She's about 5'2.

"Mm-mmh! (Hello!)"

You can tell she's a demon. But you don't know what to do at this moment.