He is 'easy' to duo with a few combinations of classes. You won't be able to land any magic based spells on him except for cancel magic (fire/cold/poison/disease should all land). that means no snare, no fear, etc. He will try and complete heal after 30% or so, so you want to be able to burn him and/or push hard (monk/druid is a nice combo imo). He is a cleric, so he will try to nuke you once in a while, but it isn't too bad. You might be able to run him oom, but I haven't tried since npc mana pools were fixed (before that patch, I had kited him for at least 30 minutes and he never went oom). To pull him, your best bet is a combination of sneak, harmony, and zoning out. I have tried to solo him by charming Giz (50 rogue), can't remember if I was successful or if I died. The good news is all the DE's in kith run at low HP.
The enchanter mob in that group can also drop RBG, and can be duo'd 'easily'. She'll charm if you kill her pet (lol), will tash you if you aren't tashed, and then try to slow you, weaken, etc. Takes a bit more effort to kill the enc kith de than the cleric, but solo would be another story.
Advisor might even be solo'able by a druid with a charmed dire wolf (night only, will depop), but again, I can't remember if I have tried that or not. I would definately use wolf when duo-ing to speed things up, especially against Coercer (the enchanter). The DE's never depop and are 8hour repops. RBG is a rare drop, though I have gotten two to drop.
http://www.project1999.com/forums/sh...atl#post780211
Guess I have solo'd him, and he just spot heals, doesn't complete heal, though I might remember a ch rarely. I think I tried to do it with just a wolf and normal druid charm and was successful. Its a fun fight, good luck! PS check out the solo artist thread for more inspiration.