d4ca328e_f_the_Mists_FOTM_guide___Dulfy__Agony_attack_description
[Fractal] Urban Battlegrounds [Boss] Captain Ashym [Agony attack description] 
He has a proximity based fire AoE that causes agony to all nearby foes (this wipe out all the charrs) at 50% HP (preceded by a frontal pull) and then casts rain of fireballs that inflict agony on anyone standing in them. Just circle strafe.
GW2 Fractal of the Mists FOTM guide - Dulfy
Agony attack description