Late-game Town Enhancement.

If you level up Spell Power and equip a set for a Warlock, they can still deal significant damage with spells in the late game. I managed to defeat 53 Lava Dragons, which were resistant to Earth, with an enhanced Shock Earth spell that had a Luck bonus, and this was without Emerald Boots. If Chaos isn't working, you can try using summons or Darkness spells.