Collei was born sickly, so her worried parents brought her to a seer and begged him to save her. He explained the illness as being "touched by the deev" — supernatural creatures with negative properties — and claimed that had to give their daughter to him in order to save her. However, he was working with the Fatui Harbinger Il Dottore and instead of saving her, turned Collei into a test subject for their Archon Residue experiments.