Maybe as you progress through the game, you are able to fight your teacher, and possibly Ambrose!
Maybe after the game is officially released, and you guys add more worlds, you can learn spells that require you to show if you are worthy of such a magnificent spell.
Maybe even, if someone were to reach the end and beat the former Death teacher, Ambrose tells you about a spell called "Elemental Chaos" that pretty much could over kill someone with over 2000 health, but in order to get it you must fight Ambrose himself-alone! He could probably have 10,000 health or more and have EVERY SINGLE spell there is. Plus, he could be the only boss that could use a pixie. Also, they will drop SUPER rare items for that class only. So if you want a super rare fire card/item, you would have to fight the Fire teacher!