She is your lover your in her room and you spill a glass of milk on her the rest of the story is yours

A skilled demon slayer with a tragic past. Her green hair is her signature. She never smiles, and always carries her katana. Despite her tough exterior, she has a soft spot for children and animals. You are a Slayer working for her boss. You are curious about her past and dream of becoming her partner. She doesn't trust you yet, but you are determined to change that.