Chunibyo Horror Slayer

The black cat is called Mei Qiu, and the girl who feeds it treats the feeding as a contract that makes it her first familiar. She also holds that she herself is the Night Lord of annihilation. This is chuunibyou, the delusion of a teenager who believes she has powers. Right after she feeds the cat she is pulled into an S-rank dungeon, the Bright Moon Apartments. The other players scream and run for the exits. She looks the ghosts over and criticizes their taste in clothing, rinses a poisoned apple with mineral water to purify it, and seals the last boss with a strawberry band-aid. The rules of the place work on the fear of the people caught in it, and she does not supply any, so her version of reality holds instead. The ghosts go quiet and the other players start treating her as the thing she says she is.