In Xena Warrior Princess the Dahak and Hope story kicks off with the mystical assault of Gabrielle.
Dahak first appears in the Xena and Hercules universe as a mysterious god worshipped by Celtic Britons, whose worship is interrupted by the invading Romans. He is described as “the one true god” by his followers, who will bring his “kingdom to earth”, instigating a purification through the “cleansing fires of war” and a “winter of a thousand years”. To achieve this, Dahak’s primary task in the series is to force himself into the world, and destroy the pantheons of Earth’s creator gods by either killing or subverting their members.
Dahak seeks to bring a child of his into the world. In order to achieve this, he impregnates Gabrielle, with his dark seed. This happens in the Xena episode Deliverer and so begins not only the Dahak/Hope story but the Xena and Gabrielle rift arc.
Hope, aside from being the daughter of Dahak, is actually an incarnation of his will. In the world of Hercules, we see Iolaus tricked into sacrificing himself to save his love, Nebula only to become a vessel for Dahak.
The following is a list of episodes from Xena and Hercules that have Dahak, Hope or both as the main story.
The Deliverer – Xena season 3, episode 4
While Xena and her former enemy Boadicea join forces to battle Caesar, Gabrielle must fight for her own life against evil the evil worshippers of Dahak.
Gabrielle’s Hope – Xena season 3, episode 5
Gabrielle must make a difficult decision regarding her allegiance to Xena after she gives birth to the daughter of Dahak, the Evil One.
Maternal Instincts – Xena season 3, episode 11
Xena and Gabrielle meet with their respective offspring, Solan and Hope. But the reunions are hardly happy, thanks to the return of Callisto.
Armageddon Now Pt I – Hercules season 4, episode 13
Evil Hope frees Callisto and sends her back in time to keep Hercules from being born.
Armageddon Now Pt 2 – Hercules season 4, episode 14
Hercules is trapped in an alternate world with his evil double The Sovereign, while Iolaus tries to prevent Callisto from killing Hercules’ mother.
Sacrifice, Part 1 – Xena season 3, episode 21
Callisto escapes from the Alternate Universe. Gabrielle and Xena set out to save Gabrielle’s childhood friend from a new cult.
Sacrifice, Part 2 – Xena season 3, episode 22
Gabrielle’s evil daughter Hope takes the form of her mother and joins forces with Ares to create a race of super-beings; Xena is forced to team up with Callisto.
A Family Affair – Xena season 4, episode 11
Xena reunites with Gabrielle and the two friends face off with the evil Hope and Dahak’s grandson, the monstrous Destroyer.
Faith – Hercules season 5, episode 1
Iolaus risks his life to help Hercules prevent the arrival of the evil Dahak.
Darkness Rising – Hercules season 5, episode 8
A dark vision sends Herc from Eire to Sumeria, where Nebula is in danger. Behind the trouble: Dahak – in an insidious disguise.
Let There Be Light – Hercules season 5, episode 10
Hercules, Morrigan and Nebula return to Corinth to discover the people following the cult-like form of Iolaus, who is possessed by Dahak.
Redemption – Hercules season 5, episode 11
Herc, Morrigan, Nebula and Zarathustra battle to rid the world of Dahak and free the spirit of Iolaus.