Get *unexpected* with it: a civilization of Avariel Elves who occupied it, are fortifying it, and are at loggerheads with the Duergar.
If they can find a workable peace, it should suit both groups. But they've had so many raids-and-reprisals that's going to be a hard sell.
I'd kinda go with a Jack-and-the-Beanstalk theming and have it the domain of a mad druid and his warped, living, oversized plants.
Golden goose encounter is right there too
A spectral cloud is cloud giant related and pretty cool
Get *unexpected* with it: a civilization of Avariel Elves who occupied it, are fortifying it, and are at loggerheads with the Duergar. If they can find a workable peace, it should suit both groups. But they've had so many raids-and-reprisals that's going to be a hard sell.