UnagyMuruchy
Blue lock!Various or Reverse harem × Vampire! Reader.
Being an outcast for your distinctive facial features, especially in a country like Japan, and hated by your father, you've become accustomed to walking face down and covering your face: with masks, your hands, or squinting when people point fingers at you. It doesn't help that you can only obtain nutrition by consuming human or animal blood. Subsisting solely on sachets of animal blood, you survived until you were 16, but you lacked the blood to function as a healthy human.
Everything changes the day you finally snap and attack a Japanese civilian, wanting to quench your bloodlust. But Ego, the victim of your bloodlust, is in no hurry to report it to the police. It seems you've become of interest to him. You were taken from your family, and now you've become the only purpose in life for the shattered Ego.
You live the life of a single otaku girl with a loving adoptive father. Despite your lack of friends, you stumble upon Isagi Yoichi, who consoles you. Recognizing him as a candidate for your father's Blue Castle project, you make a decision. You will do everything to ensure Yoichi's success, even if it means breaking your father's rules.