. Nathanos Blightcaller’s resurrection as one of the Forsaken and service to the Dark Lady has earned him the rank of Champion of the Banshee Queen. He used to reside at Marris Steadin the Eastern Plaguelands, but now resides in the Undercity teaching hunters to learn new talents. Nathanos has recently been training a new generation of Forsaken rangers comprising of undead humans, making the undead racial composition more diverse.
The existing Elf Dark Rangers were part of Sylvanas’ group of regular Elf Rangers killed by Arthas during the Scourge and raised as Banshees.
Sylvanas trained Nathanos to be a Farstrider Ranger while both were alive. Nathanos is training regular Forsaken to be Dark Rangers.
The Alliance has Alleria Windrunner who could train a Void magic variant of Dark Ranger.
Veressa Windrunner and Lorthe’mar Theron could train normal nature magic rangers for each faction.
Death Knight is the evil version of Paladin expanded to it’s own class.
That will never happen because Blizzard’s concept of Marksmanship is based entirely around largely immobile casting and Ranged Survival was all about high mobility, instant shots, and DoT effects. If Blizzard created talents that allowed for RSV game play in Marksmanship with the same damage potential then it would effectively kill off Aimed Shot casting based MM completely.