So here's a material for Desril.

Demonthread silk.

Demonthread silk is only found in the abyss. On layers devoted to spiders and all their villainous ilk.

Demonthread silk gives armor many valuable abilities, in exchange for being much harder to remove then other materials. Any metal armor can be made out of Demonthread silk which causes the following changes.

Wearers ignore fatigue and exhaustion effects.
The armor's max dex is increased by +1
The armor can be made transparent at will.
Removing the armor makes the wearer take 1d4 points of damage if light, 2d4 points if medium, or 3d4 points if heavy unless a DC 25 heal check is made, as the hooked anchoring barbs are torn out of the wearer's skin.

Demonthread silk costs an additional 9000 gp over the normal armor.