Nightmare paused and calmly looked at Rarity. "Be that as it may, I was brought to existence in Mareitania, by accident on Luna's part rather than Twilight's. I was however trapped in the dreamscape until Faust found me and tore me out. Then she made her worst mistake and gave me a body, making me a proper alicorn rather than a figment in the dreamscape. She also destroyed her ability to destroy me by doing so, which is what brings us here."