Note: the fight of 3 waves mobs and the boss are very important if you manage to solo the quest. the 1st and 2nd waves can be damaged by Sancturay, Turn dead etc, but the 3rd wave are 3 Mr. Pumpkin with fire property, you can only damage it with melee attack. Try to go with a good hammer!|
The boss is a weak Evil Poring with shadow property, it is best to damage it with Magnus Exorcismus. This EP is located at the bridge and will come back to bridge if it chases you too long. Cast Magnus Exorcismus in the far distance, lure, and let it chases and it come back could be the dmg circle. It wouldn't heal itself.
Become a high priest earlier!