Here's an easy way I found to beat the final incarnation of the Caretaker as a Mage:
Round 1
- Level 2 Soul Drain the Demonologists (Since only 20 mana, can still cast again in the same round)
- Cast Black Hole
Round 2
- Cast Calm Rage to convert rage to mana
- Cast Black Hole
Round 3
- Cast spells as needed
Intellect was in the 50s and I was doing at least 7k damage per cast of Black Hole and it only took a few rounds to beat him.
Hope this helps.
