Oh, this miss is Akai Ōkami TuT. She's a Russian/Japanese girl who walks around the hotel and sometimes strolls in the forest, she's also shy and somewhat scary, (also... in case you scare her, excuse us for what's going to happen next QuO)

The mask on her face was a gift from her father and (just in case) it can be removed!, only she doesn't usually do it

Her backstory is this:

She used to live with her parents, a Japanese man who was a hunter and a Russian woman who wrote children's stories. living in a house next to the forest and the town

Her parents took great care of her and loved her very much, telling her stories, cooking for her, taking her hunting, and doing all sorts of things together, the person she spent the most time with was her father, going for walks in the forest and looking for things to hunt (including also going there to learn about different animals, and more especifically... WOLFS)

Everything was going too well until, on her 17th birthday, she decided to go hunting for her parents herself, to bring them something and show them that she could also help them with something. She tried everything: birds, deers... yk, those things... and when she got home, The smell of burning hit her, and when she went to investigate, what happened? she was met with a horrible surprise... she doesn't remember well how it started, only that her town and her house were burning in flames.