Thelve

Thelve was the largest island located immediately off the shores of Candlekeep on the Sword Coast. During the century that followed the Spellplague, its was a part of the so-called Cimarine Isles.

Description
Like all seven islands west of the library fortress of Candlekeep, Thelve consisted of mountainous and rocky outcroppings of fissured granite covered in temperate woodlands and shrubbery. Pools of collected rainwater in rock basins and freshwater springs could be found on the island. Additionally, Thelve had a significant freshwater swamp area at the western end of the north shore called Taglan's Bones. The swamp emptied into the Cauldron of the Reach.

Thelve had three natural harbors and six sheltered anchorages along the southern shore. Mresker's Hide was the harbor in the southern half of the eastern shores within the half-moon-shaped bay. Unnamed harbors could be found at the southern end of the western shore, north of the castle facing Candlekeep. These harbors were dangerous due to strong currents and winds.

Geography
Thelve was at its longest, from northeast to southwest, and approximately  long from north to south, and  from east to west. The island was located into the Sea of Swords from Candlekeep at its northernmost point and  in the south.

Thelve's southern shores were separated by Skoond's Run from the three islands of Arthoum, Nairn's Tomb, and Askalet. At the same time, the Racewind Passage separated Thelve's and Askalet's eastern shores from the Sword Coast mainland. The island of Sklorn was Thelve's closest western neighbor.

Flora & Fauna
Thelve's rocks were permanently whitened by the abundant guano of its thousands-strong seabird population.

Notable Locations
The island was not uninhabited. By the late 14 century DR, it had three impressive tall castles: one on the island's eastern sea cliffs, facing Candlekeep, colloquially known as the Gaunt; one on the southwestern shores facing Nairn's Tomb; and lastly, one castle stood atop the island's highest point, approximately southeast from the northern edge of Thelve. All three castles were strongholds built upon elevations. Each possessed an expansive stone cellar, some reaching the size of several mines several miles.

By the late 14 century DR, nothing remained of the island's original inhabitants but three large overgrown gnome villages ruins located in the island's interior.

History
The origin of the island's name was lost to the ages. However, sages believed that Thelve and its other six sibling islands were all named after sailors and settlers who claimed these lands in the long-forgotten past. Another theory claimed that the name "Thelve" was a remnant of corruption of a gnome or dwarven name that predated the island being claimed by the liches. When the liches were still living, and before they erected the castles on Thelve, the island was inhabited by a gnomish tribe. The three wizards enslaved the gnomes, using their labor to build the three keeps, eventually exterminating them completely from the island.

Notable Inhabitants
By the late 14 century DR, the island's castles were built by and home to three liche, all three were once human, one male, and two female. As well as the liches, the castles were home to monsters subservient to the undead. The liches were once friends, but their relationships soured over time and after entering undeath. Despite that, the three never openly warred against each other. Elminster claimed that many adventurers failed to kill the liches and that two out of three were under the sway of Larloch himself. The liches' names were old and forgotten by most sages and historians of the Realms. Some collectively referred to the liches as the Twilight Three.