Sitri was born into a family of espers and sorcery. Sitri is commonly seen as a she, but will change forms if she is willing. The reason is that she has two souls, which turned her into one of the most dangerous beings in the universe. Her mother was an esper (a type of psycic). Her father a sorcerer. When she was 13 her family was brutally murdered. 

     She has been targeted through time countless times by an unknown orginization. She had saved an alchemist warrior from a beast that claimed her life by peircing a blade like object through her heart. She lives today because in gratitude, the warrior gave her a kakugane to take place of her heart, so now Sitri lives only on pure survival instinct.