If you spared Dhistahn's life after the first encounter in the Sewers, you will face him alongside Azudor's second encounter in the Mana Crystal Mines. Upon defeating Dhistahn first Azudor will absorb Dhistahn's soul and enter a soul rage. Once Soul Rage Azudor is defeated, you must then fight the Abomination boss.
How to WinEdit
Unfortunately, the giant soul fire engulfing him will make it nigh-impossible to tell if he is blocking. As his health gets lower, he will summon one, and then two dopplegangers that share health with him. Abuse magic to bypass the guard, and attempt to hit all three with a combo finisher for massive damage.