War and a Vampire

Freya Celestia, a girl who deluded herself on training in Althan Corps, a Demon Slayer corporation that was founded by her own father in order to protect Humans from demons who took over the world. Freya grew up hating Vampires. Vampires who once invaded earth and took the life of her own mother. But as time went by, Vampires and humans fought together to fight the demons who are trying to take over the earth. Because of her eagerness to catch up to her own sister and to protect humans from demons, she had to accept being partnered with an emotionless bloodsucking vampire.