I have found that if you get there with at least one credit,you can just keep on a corner and use magic till you have no energy,then try to hit him the most you can till he kills and repeat,he will die eventually. Shield characters have an easier way,as you can just attacking and guarding against it s devastating fire. Ranged characters better use the first way. Watch out for his hand,it does an exagerated ammount of damage. Some of them can be only accesed by some characters.
Fire comes from the floor and damages.
The weakest of all magics. Hits up to 4 enemies. Standar magic for the Dwarf and Fighter. Electric rays come from the skies and hit up to three enemies for a good damage. Standar magic for the Widzard,Elf and Cleric.