| Category | Resources |
| Type | Ilmanómë silk |
| Source | manufactured |
Haelssysn Weave is a cloth-making procedure that utilizes a rare and challenging-to-obtain spider silk. The silk originates from a deadly abyssal spider known as the Ilmanómë. Residing in the Demon Web Pits, these are exceptionally resilient arachnids, capable of firing virtually indestructible web strands. The spider's own venom is employed to dissolve the silk. The drow of Phaerssysn were the first to harness Ilmanómë's silk. The art of weaving this spider silk with cloth is titled the Haelssysn Weave, named after the drow house that invented the process.
The Haelssysn Weave augments the defensive capabilities of robes, drench-coats, and other full-body cloth garments. Within the city of Phaerssysn, the affluent openly don the Haelssysn Weave as a demonstration of their wealth and status.