Hello, this is about a manga i read ages ago, it started as a one-shot, i think.
It was about a girl that can turn into a black cat of various sizes. if i remember correctly she had twin-tails...
The manga's world is about animal deities that are connected to certain families and each animal represents a family or something like that,
these families help each other from time to time and some are hostile(?)
Anyways. at the begging of the story, if i remember correctly, the girl is trying to kill the mc in her black cat form because she wanted revenge for a certain promise the mc family made to hers (not really sure about this part tho)
And... well, that's all i can really remember so if anyone can help me find this it will be very appreciated!