Shades of Darkness
The Shades of Darkness is an organization introduced in Dragon issue 387. Below is an excerpt of the article with additional details pertaining to Rhinec specifically.
Wickedness might thrive in the Shadowfell, but not all welcome its presence. Some recoil at the growing corruption and are appalled at its free reign. Several of these good people take the fight to the darkness in the Shadowfell just as others do in the world beyond, and a few organized efforts against the interlopers have gained strength. Among them, none instill more fear than the Shades of Darkness.
The Shades of Darkness is a moderate-sized organization spread across the Shadowfell, natural world, and elsewhere. Spread as widely as they are, most agents work alone, hiding within other groups, adventuring parties, temples, and secular institutions. Isolation means agents can go years without contact with the larger organization, and many go their entire lives awaiting orders that never come. Others, however, find their lives shaped by the Shades’ goals, undertaking mission after mission, often with little explanation for their purpose or consequences.
The Shades of Darkness group was formed long ago by a mysterious figure named Mourne. Few believe the lich exists today, though rumors claim that he hides in undead-infested tunnels below Gloomwrought in the Shadowfell. A refugee from the natural world, he retreated to the Shadowfell’s darkest corners, losing himself among Moil’s icy towers where he could study the dark arts without interference. Legend holds Mourne was of two worlds—one light and the other dark—a child from an unhappy union of drow and eladrin. In his cursed blood, he found the penchant for wickedness his magic demanded, but in the light he felt shame and guilt for the evils he worked.
Collaboration between the Shades of Darkenss and any other group is seldom heard of. The path it’s members walk meanders into territory other guilds concern themselves with, usually resulting in conflict. The most nutorius instance of violence between the Shades of Darkeness and another organization was recorded long ago involving the Order of the Crimson Night. While history has no details of the incident that occurred, assassin guilds as a whole are seen as enemies ever since.