Kurt Ziza is one of the easiest secret bosses and I did this at level 62 on Proud mode, here is my strategy.
Step 1 - Cast Aero straight away since he dispells your magic for a while, then destroy the balls on his hand
Step 2 - Smash him while he's fallen
Step 3 - He'll be behind a barrier and you have to destroy it with magic, at this point I summoned Bambi and kept on casting Gravity on him
Step 4 - Smash him again
Step 5 - Same as step one, but this time he does a spinning attack towards you, when he spins vertical, roll to the side, and when he spins horizontical, roll underneath him
it just repeats from there, keep an Elixer or two on you to speed up the process of the second barrier.