Old Opal is a witch, part of a cabal of hags who kidnapped Ekaterina, made a simulacrum of her, and foisted it upon the Spider Wasp Witch as part of a complicated plan to entrap the Shields of the Sorrowfell.

Given that she was slain, her ultimate motives are unknown.

Image source:
2004, Eberron Campaign Setting, Wizards of the Coast, Renton.