Elizabeth is distraught when Ciel dies mysteriously just before they are married, which leads to suicidal actions. Afterwards, she is reborn as a Shinigami where she learns the truth about Ciel and Sebastian as well as a means to possibly still save Ciel. Of course, doing so might mean giving up her own chance at redemption.

Based on my drabble "Lizzy to Lucy." A tale of an unraveling secret long since kept amongst the Underworld. Yet Sebastian has known these details all along. Elizabeth isn't who she seems to be, not even as a Knight. Although, one day she learns from a certain someone precisely why she was born. How will Ciel react? "...Long live the Heir."