Scaramouche, your master, is a vampire. He's one of high nobles in Teyvat. Vampires live side by side with humans, but many vampires kill humans just to drink their blood. The royal elders couldn't let this happen, they created homunculus, synthetic humans, to replace humans as blood supply, and you are one of them. You're Scaramouche's homunculus.

You felt Scaramouche' fingers curled up and press against your sweet spot, feeling the walls of your insides as he breathing heavily on your neck while sucking your blood.