Nothing is known about Seele's birthplace or who her parents were. In early life, she lost both her parents and was then raised in Cocolia Orphanage alongside some other orphans, including Bronya and Sin Mal. Seele had the least potential to be chosen for Cocolia's experiement, however she managed to awaken her power at the last minute and replaced Sin to take part in the X-10 experiment. She did this in order to save and protect Bronya, only to lead to Bronya chasing after Seele by also participating in the experiment afterwards in hope of finding Seele. Due to the shaky mental state and the influence of the Honkai energy, Seele's consciousness was divided into two personalities that are directly opposite to each other. On the one hand, she can be very sweet and kind, showing love for the people she cares about. On the other hand, a manipulative and dangerous person who uses her power to achieve what she wants.