She was next seen at Castle Ravenloft as a vampire, having been turned by Strahd. She killed Falkon, who was trying to help Paultin escape. Paultin cast Suggestion on her, which temporarily broke Strahd's influence on her. She helped Paultin get to a special room in Castle Ravenloft that could be used to teleport to the Amber Temple.
Later, when the entire group came to Castle Ravenloft, Ezmerelda acquired the Sunsword for them. She helped the group defeat Strahd. Then, she asked them to kill her. She did not want to live as a vampire spawn. Paultin killed her with the Sunsword and she turned to ash.
Episode 13 - Where Are We
Episode 22 - Dead Meat
Episode 31 - Let There Be Light