Heaven's Warrior (Seraph of the End x Reader x OC)

[CURRENTLY REWRITING - ON HIATUS] After the spread of the virus and the start of a so-called apocalypse, Yuu, Mika, and their small family are taken by the vampires to a life of slavery and blood. Trapped, they fear for the worst but hope a girl that knows too much but says too little can help them escape. Mysterious...