Caught him up walking on the wall today. Set up on east side of the walkway, killed a few rovers and the static giant at the end of the walkway. Pulled Belgar, Captain of the Wall easily enough. Simple fight, no adds on pull, Belgar didn't summon any help, never saw or felt any type of AoE, snareable, no enrage, x2 times on rampage. Pretty easy for a level 80 mob. Dropped belt/chain powersource. Keep the bridge and all mobs on or near it cleared for the next two hours, didn't see any more Belgar's. Had tracker in group, didn't him see again.
Spawned in the west tower, had adds on the pull which I Feigned off then the guard captains ganged up on him and killed him so apparently he isnt on faction with them.
We killed him 3 times and was suprised that 2nd time he poped in the east tower. Other 2 times, we found him at east end of ramparts, above main city gate. Belt is the common drop it seems.