Knight. I just did the first epic (already did it once at armorgames) and if you have the right skills it isn't too hard. Just maximize lower mana cost, number of basic gems and higher initial/max mana and put the rest of your points on mana gain per kill and you should be fine.
You should be able to hold of the first wave with the starter gems (combine). try to raise your mana, so you can buy lvl5 or 6 gems and get a few of those.
Place a load of trenches and bombard the final boss if the gems didn't kill him.
he was dead before he was halfway with me.
kvoorneveld's comments