Overlord

Watch the colors of the shields the wizard is using and send your minions of color to break them. He'll fall to the ground after each breakthrough and then you can sen all your minions to him and assist them with your powers and weapons. Dodge his attacks and collect stuff from the barrels around the arena - surely you'll find some goodies there. There are spawning pits on the sides too so you shouldn't run out of minions. The bad thing is: there are lots of the crazy ones and they are particularly annoying. The best way of dealing with them is to use your spells of mass destruction.

Grab about 30 greens and 20 browns and sit in a corner on top of the spawn pits. Use the browns to defend you and the greens when the evil minions attack, use the greens to attack the wizard when he emits the green field. When the wizard does the whirlwind attack get all the minions in the corner by the spawn pits. When the wizard is about half health you will be warped to the center of the arena and will have to fight to get back to the spawn pits, once back continue as before until the wizard is brought to his knees.

This guy is not bad, as long as you know how to defeat him. When he puts up a barrier, use the minion of that same colour to attack him and his barrier will break, causing him to fall onto the floor. Run in and smack him with your weapon until he pushes you away. Dodge his sweeping attacks and his whirlwind (move your minions to the side areas or the entry). He'll send waves of evil minions at you as well, so kill them too. Just keep up this strategy until he falls, it won't take long. Enjoy your ending!