Source: Isles of the Shackles, pg(s). 20
Heslandaena is a subterranean settlement below the island of Dahak's Tooth in the Shackles. The cenotes that dot the island offer aquatic entry to miles of sea caves, which eventually emerge into unflooded, humid caverns. These moldy dark caves and passages lead to Heslandaena. The isolated town is inhabited by drow cut off from the Darklands many years ago by a curse.
The dark elves were part of the Harkule clan. They offended a powerful matriarch and were banished for their insolence. The isolated drow town is ruled by matriarch Pelanquelle, wicked and resentful for her exile. A number of pirate captains know about the drow settlement and are trusted by its ruler: Adis Vraisdottir, captain of the fast sloop North Wind, which sails out of Mezdrubal; White Hollis Dobilo, captain of the brig Stormrunner, which sails from Drenchport; and Constanza Purgote, captain of the sloop Constanza's Whim which sails from Port Peril.
The three pirates, each unaware of the others, all have lucrative trading deals with matriarch Pelanquelle bringing foodstuffs and supplies in exchange for raw gemstones and rare subterranean substances.