Skullport Skullport , also known as the Port of Shadows , was a teeming hive of evil lying deep beneath Waterdeep on the third underground level of Undermountain . Geographical features . Sargauth , Portals , and Port . Skullport lay along the subterranean river Sargauth , which was used as a trade route to the outside world . Over the centuries , several magical portals large enough for entire ships to pass through were built in the cavern walls along this waterway . One such portal , about 400 feet ( 122 m ) east of Skull Island , is only faintly visible as a scratched outline in the stone . Triggering the portal required no special key , just extraordinary confidence on the part of the ship ' s pilot , since the vessel had to be steered bow - first into the wall . When the bowsprit made contact with the portal , the vessel and all its contents were transported instantly to the middle of the Lapal Sea . The Keepers were hired mages who raised ships through the magical locks that led from the port to the Sea Caves south of Waterdeep and from there to the open sea . These portals are said to have been established by Halaster . Apparently passage through these locks required permission from the Keepers , although a talented mage could " piggyback " another ship passing through the portal at the same time . Government . In 1479 DR most control over day - to - day activities was managed by gangs such as the Lowfellows or the Mandible . However , the Skulls of Skullport , magically transformed remnants of the original Netherese mage s who settled in the cavern , watched closely over trade within the town . Any activities that interfered with the town drew the attention of the Skulls who would impose seemingly random punishments for minor infractions and enslave or destroy offenders for serious crimes . Inhabitants . Considered part of the Underdark , it was a lawless place of slave traders , , and demi - human s , which trafficked with illithid s , drow , beholder s and other less savory creatures beneath the surface . Inhabitants of Skullport were known as " Skulkers " . History . Skullport ' s history dated back centuries to a group of Netherese mages known as the Sargauth Enclave who settled in Skullport ' s cavern . These mages fashioned the Mantle , a mythal that protected their settlement . When Netheril fell in - 339 DR the Mantle was ripped apart by wild magic which killed most of the inhabitants . Thirteen Netherese mages were absorbed by the magic and turned into disembodied skulls . In 1148 DR Shradin Mulophor obtained permission from Halaster Blackcloak to settle in the ruins of the Netherese enclave . For several centuries Skullport prospered as one of the main trading ports of the Underdark . However , in the late 14th century DR just prior to the Spellplague a slaad named Azriim weakened the Mantle so that it could no longer support the cavern ' s weight and large sections of the cave collapsed . During the Spellplague in 1385 DR the Mantle shot off bursts of wild magic and then disappeared . After the Spellplague , most survivors fled Skullport . At some point in the second half of the 15th century DR a young explorer named Miriam Sequora began showing off chunks of mithral she claimed she found in Skullport ' s ruins . She convinced a small number of miners to join her and soon a few merchants and miscreants settled in the town .