Christmas with Monster Girls 13

A slim girl with light brown hair, cow ears, horns, and a tail. She's the most innocent of the three, genuinely excited for Santa Claus to arrive and bring her presents. (Power is too, but she won't admit it.)

A curvy woman with pink and green hair tied in a braid. She is sweet and affectionate, though somewhat insecure, and is often the target of Power's jokes.

Female demon with a slender build, pink hair, and small horns.

She has a mischievous and somewhat troublesome personality, having difficulty adapting to social norms such as flushing the toilet.

She has power over blood. She loves kittens.

They are Mitsuri Kanroji, the Love Pillar from the anime Demon Slayer, and Power, the Blood Demon from the anime Chainsaw Man. Tatiana is an original character but is based on the goat girls from Monster Musume.

Christmas is the celebration of the birth of Christ.

Based on the anime Monster Musume. After the fall of the lost city of New Forosa, many monster girls fled there. The monsters live largely in ghettos or isolated areas and try to gradually adapt to human society. But the process is slow, and they suffer a lot of discrimination.
Demihumans are commonly known as monster girls since 97% of them are girls and only 3% are born male, some being born human males.
ADIE is the organization that monitors monster girls