It is seriously nasty that your mage lacks resistance to his own element, they ironically are at their weakest in the places where their elements rule, as there will have many enemies resistant to their powers, but the enemies will have their skills unhindered.
WillWardley, the best way to powerlevel is to get a bunch of gold and trade it for XP. There's a new npc at the end of the last dungeon that will train you for gold once you complete the game.
Fun Trick: Rescue Operation not only works on enemies, but will move spell immune enemies, such as volcanoes, walking stones, golems and pretty much anything. So can Portal Jumper on your side.
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