Isabeau died in The Great War when The Blood King's signature was forged on a dispatch ordering assassins to kill her after she went in secret to meet privately with Horvis, the leader of the Dark Fae army, in an attempt to settle the differences between the two clans and broker a peace truce (Flesh and Blood).
The Blood King, in frustration, had suggested using his blood to force a treaty between the Light and Dark; but Isabeau knew that using his Blood Sage powers to end the war would create unintended consequences.
In Flesh and Blood, Trick gave Bo a small vial containing Isabeau's life essence to protect her from being possessed by darkness when she confronted The Garuda. The liquid had incredible curative powers: it could cure illness, neutralize poison, and stave off the darkness from within.
Trick revealed to Bo that she was named after Isabeau and that it was from her life essence where Bo had inherited her ability to heal (Flesh and Blood).
- Trick: Husband. Trick partly blames himself for her death.
- Aife: Daughter. Isabeau died before Aife's rebellion against the Blood Laws, her killing a Dark Fae leader, and subsequently being convicted to death, then imprisoned by the Dark King.
- Bo: Granddaughter. Isabeau died before knowing she had a granddaughter.
Although Bo was named after Isabeau, her name, however, is spelled with a "Y" (Ysabeau).
- 2.13 Barometz. Trick. Pressure (vision) (In this episode, Alisen Down is credited as "wife".)
- 2.22 Flesh and Blood (flashback) (In this episode, Alisen Down is credited as "Isabeau".)
- 5.07 Here Comes the Night
- ↑ (see image Lost Girl Prologue (Pg 7) from "'Ysabeau', or Bo for short, was born of Fae and is a rarity in their world." - Lost Girl: Prologue (Showcase/Prodigy Pictures, 2011). Retrieved on 09/20/2013. )