"I am a stone. I do not move. I do not tremble. I have no fear." - Ebon Vanguard Sniper Support (Referencing Enemy at the Gates)
Huh, funny how things little work out sometimes. I previously mentioned being stuck on Duncan the Black in GW only to successfully finish it last night. It was actually fitting that it was using the skill Ebon Vanguard Sniper Support that finished the boss off with the quote written above the associated dialog for getting a "headshot".
Pretty much just used a minor variation of the standard swapping of spirits and Necro trick (the other player, a tank, sacrificed himself) to the dungeon adding in my Ranger's bleeding and poison conditions while the two bonder heroes and healer henchman healed damage as needed. I think it took longer to move all the spirits than it did to take out the boss.
Trivial entertainment at its finest.