In Curse Of Strahd, Elizabeth ambushed a group attempting to cut down Gustav's hanging body, but was rent asunder by Ghalwin Forrester and the rest of the Pack. They escaped the Death House after killing her and Walter; however, though she was destroyed in the resulting fire, the house's Curse remained.
Elizabeth was the matriarch of the Durst family and the Death House, noted for her wealth among the citizens of the Village of Barovia due to the family's ownership of the Durst Windmill. She was the mother of Rosavalda and Thornboldt, and though somewhat unstable, was still well-thought of amongst her peers and community.
When she learned of her husband Gustav's impropriety with his nursemaid, she divulged a plan with several other cultists, and inferred meaning from exchanged letters with her "friend" Tasha Petrovna in Krezk. She killed the bastard baby Walter and his mother Zondra Zalenski, and locked away Rose and Thorn in their room. She succumbed to madness in the depths, forgetting about her children upstairs and letting dark powers to transform her body.
On realizing what his wife had done, Gustav committed suicide, which pleased Elizabeth greatly. She headed the cult's remaining activities and lead adventurers into the Death House for a near-calendar month in hopes of appeasing Strahd von Zarovich, feeding them to the Shambling Mound created from Walter's sacrifice. However, she found that Strahd was angry at her for stealing his prizes, and the Count transformed her and other cultists into ghasts and ghouls. For generations, she vigilantly guarded her hated husband's body, which stayed hanging over their bed via the rope he committed suicide with.