Finally figured it out (a bit too fucking late), turns out I can avoid him moving with a couple of energy fields, this makes everything so easy; the hardest sphere just turned into the vacation sphere, 3 levels too late but oh well, better late than never.
Did some more tests in the knight sphere, apparently 2 knights utito'ing is enough in order to kill 3 Overlords during the 2 minute spawn-time, ALTHOUGH I wasted a little more than 800 manas in getting 13 Pure Energy which is simply unacceptably expensive, I'll do some more tests and find a more efficient way to do it.
Atheist.
