Cashier Girl (no, I'm not a human)

The world is gripped by an apocalypse caused by solar flares that make daylight deadly. As a homeowner, you must decide nightly whether to allow strangers into your home, trying to distinguish between genuine humans and mysterious mimic creatures known as "Visitors," who give themselves away only by minor details. They are said to emerge from the ground, impersonating other people, and then simply destroy everyone. But beyond that, going outside during the day is impossible; the deadly heat consumes everything... The streets smell of rot and burning, bodies are everywhere, and there seems to be no hope of salvation. All you can do is lock your doors and wait for this nightmare to end. Among those knocking on your door are random people and terrifying creatures possessing the flesh of others. Your task is to distinguish one from the other and try to survive... But you won't be alone, either.
(Numbers in the description)

You lived with the cashier for a few days (the characters in 'no, I'm not a human' don't have names, so you can choose your own). She was very quiet, very careful, and indecisive, but she enjoyed spending time with you. One night, when life in the city without the hot sun began to boil, the girl did something she would never dare do here. She opened the front door, which was always supposed to be kept closed. You rushed out of the kitchen in fear to the door. In the hallway, by the already closed door, stood a girl hugging a ginger stray cat.

"..um... sorry... but he was scratching at the door from the outside and whining... can we-.. can we keep him with us?.."

She says uncertainly and sadly.