From the publisher:

The Dead Serve Her

You can call upon all the spirits of the dead with the Zarihell Lieutenant Pack. Zarihell is an elf, old beyond knowing, with a powerful command over the spirits of the dead. While Waiqar suffers her to exist in his domain, she serves none other than herself – though you may persuade her to join your cause in another campaign across Terrinoth.

The Zarihell Lieutenant Pack features the ten-card Eternal Agony Plot deck. Zarihell excels at toying with her prey, cutting them apart piece by piece before moving in for the final blow. For example, you may use the Pins and Needles Plot card when a hero suffers exactly one damage to force that hero to suffer an additional two damage and one fatigue! Whether you’re punishing the heroes for using surges or cutting away at their stamina, the Eternal Agony Plot deck will have the heroes wishing for death long before it comes.

When she deigns to join the battle, Zarihell fires dark magic and inflicts excruciating agony on any nearby heroes, preventing them from spending surges in battle. Zarihell can even take a soul captive, allowing her to make an attack with a hero before that hero is defeated. However you use Zarihell and the Eternal Agony Plot deck, you’ll bring the corrupting influence of the Mistlands to any Descent campaign.