Mato Kuroi was the child of an Otherself and a human. She had a younger sister who was the sweetest thing ever. The only thing was, Mato was born with an illness. She was outcasted, isolated; even her own flesh and blood eventually turned on her. That was the last straw; she decided that she would make everyone pay, using her illness... A/N: This fanfiction is based on the vocaloid song, "Bacterial Contamination". I suggest that you (the readers) listen to the song to really understand what's going on before reading this.