No, no the easiest way to kill the corruptor is to take off all the reflecting items(if you attack them you die) and use 2rouges with sap strenght so he can´t summon darks.
A team with cleric, warrior and 2 rouges is quite good.
Put the rouges in front, leaving the centre spot empty.
Then put the warrior in back and middle WITH A SPEAR(very good if you have the rare one). And in one corner you will have the cleric who will:
1.)heal
2.)Annoint your warrior
3.)uses the magic bolt on undeads
Give all power regen to cleric.
Rouges best attacks are: Sneak attack and Create opening(this is good, cause your mighty spearman can cause a lot of damage). Also don´t forget that sap strenght beats the corruptor.
The warriors best skills are - execute and cleave.
-Donkey
Also, i´ve found a team of 2 rouges, mage and a cleric good.
With 2 rouges beating the Corrupter is childs play. With clerics healing, it´s quite hard to loose simple battles.