The Shadow Empire of Netheril.
Once banished to the Shadowfell hundreds of years ago, Netheril returned with the upheaval from the Spellplague and now works to recreate the empire they once had in Faerun. They are currently in open conflict with the nation of Thay. Parking a floating death fortress on Thay’s borders tends to provoke that sort of response.
Ovid is an AWOL agent of Netheril, sent to the Neverwinter Wood in search of…something. A limited number of other Netherese agents in the area are aware of his fugitive status. As a Scion of Shadow, Ovid must decide how to work against the Netherese without tipping his hand.
Netheril seems to have a presence in Neverwinter itself. The Shard of Night, the floating top of a tower over the River District, is occupied by shadow wraiths and contained a poorly anchored portal to a Netherese ruin in the Neverwinter Wood until the party intervened.