Information-Before You Read

Meet Ritsuka Tachibana. A year ago she had been thrown into a life of Devils and Vampires. Both species in search for something called a grimoire, in which she later ended up becoming.
Now meet Y/N L/N, a Werewolf. Three years ago she had run away from her home with her best friend Shi Taeyou. She had also stolen one of her people's most prized possessions.
When four certain Devils from Ritsuka's past return, and end up being in search for Y/N's help, what might just happen?