A century ago, a mul defiler named Yarnath used a powerful ritual to create a crawling citadel of bone in the wastes south of Tyr. However, the ritual took an unexpected turn, and Yarnath drained his own life as well as those of the slaves he intended to sacrifice. He passed into undeath and became a powerful lich.
Despite the unforeseen sacrifice, Yarnath’s ritual succeeded in animating the fortified palace of Slither to serve as his roving citadel. Slither is built from the gargantuan skeletons of seven mekillot dirks bound together by beams of fused bone. Turrets and sharp spires of bone rise crookedly from the dirk-shell structure, which slowly crawls across sand wastes, scrub plains, salt flats, and ridged foothills with equal facility.
Yarnath leads a band of raiders who primarily target trade caravans on the way to Altaruk or the Silver Spring Oasis. The lich’s marauders hide their citadel a quarter-day’s journey from wherever they set their ambushes, so no one realizes the secret of their mobile encampment. The raiders bear snake-skull tattoos, and Yarnath has established a network of spies and agents from Ledopolus to Silver Spring