Dark One

The Dark One is the wizard Quest nemesis.

Strategy
The Dark One is not very difficult to kill. He carries the Eye of the Aethiopica and thus is magic resistant.

His level allows teleport, so you can sneak up on him, grab the Eye of the Aethiopica after he teleports to the upstair, bag it, and teleport to the upstair to allow you to unload with spells such as magic missile.