Nekonoyama Neneko wa Nekoninaru

Nekonoyama Neneko is a demi-human high school girl who can turn into a cat. Trying to hide her true identity from the world, she is shy around other people except for her family. The only outsider she trusts is her older sister’s friend, Mashiro. Neneko can't help but be drawn to the cool and mysterious Mashiro. One day, Neneko discovers that Mashiro is a vampire, and she proposes living together as her blood donor (partner). This is a romance between girls clumsy at love.

(Source: Kadokawa, translated)