You really need to adjust his roaming in Traks Teeth, as he has a tendency to wander right across the Pained soul camp which can be very annoying for those folks trying to keep good faction with FV.
The name is The Night Warder Factions Increased: Pirates Of Gunthak +5 Legion of Cabilis +5 Factions Decreased: Inhabitants of Firiona Vie -100 Storm Guard -75 Emerald Warriors -75
I ran into this on my Ranger during bonus faction as I attacked it thinking it was a normal undead mob and saw the 150 hit. All I did was not attack it next time and let the group kill and I didn't take a faction hit. He will not aggro good faction and if he aggroes people they most likely KOS anyway to FV. If you con him as goodie you should still be indif or dubious unless you killed him over and over or had ruined your FV faction another way.