"He's not a cat. Not exactly. I'm not sure how much you know about Japan's mythology. I'm not too familiar with it, myself, but my counterpart has told me some things. But he - Kumori - is a bakeneko, and I'm so, so sorry, darling, but he's the one responsible for what happened with your mother."
She gave her a pause, a moment to let it sink in. She didn't know how much she'd have to explain beyond that - how much she could explain - but she would certainly try her best.