Darkness In The North
One of the Raven Knights who directly serve the Raven Queen. Gaunt humanoids fully possesed by the darkness of the Shadowfell, these powerful warriors act as regional officials of a sort, maintaining order among the realm of the undead. All have pledged their honor and their loyalty to the Raven Queen.
The Raven Knights command several companies of Shadar Kai similarly sworn to serve the Raven Queen, of which your allie Ovid Merchuryl is now a member. These companies are housed in small keeps that dot the perphery of the Shadowfell; each keep is under the command of one or more Raven Knights.
The typical Raven Knight keep is a single narrow tower that rises high enough to command a view of the surrounding land. In this way, the Raven Knights help protect regions of the Shadowfell from other powers. Primarily, they keep a lookout for agents of Orcus attempting to slip into the realm unnoticed.
Because of their service to she who rules the Shadowfell, Raven Knights are honored in shadar-kai cities. Indeed, some Raven Knights were once shadar-kai who were singled out by the Raven Queen and made into exemplars in her eminence’s service.