Gloam Essence

Recovered from Azzrukhan's stash

Acts as copying/scribing ink for spells, double effect for Shadow/Darkness-based spells. Can be infused into a rope and burned as incense.

[Arcana - 37]
This Gloam Essence is actually just processed and refined blood taken from a kind of undead creature called a Gloamwing. They are native to the Shadowfell and said to be "made of solid shadow".

Theories

How did Azzrukhan get access to it? Does the Planar Binding still allow them to cross into the Shadowfell? Do they have access to a portal, or to someone who runs smuggling / logistics through it?