Dungeon Defenders II

Lightning auras are the monk's final kind of tower. He will unlock this tower about level 20. Add the Monk to your "deck" (meaning equip him as one of your heroes.) Then level him up by playing missions with him in your deck. You don't actually need to use him. Switch to him during a build phase, and hold to bring up your towers. Press to select the Lightning Aura, and A to place it. It will deal damage to all enemies in its area of effect every couple of seconds. Upgrading with + will increase the damage.

Use a lot of upgraded Lightning auras at once to unlock this quickly.

this is the monks + trap ability. what i did was do the very first level (The Gates Of Dragonfall) and put the traps all the way down the path from the enemy gate to the crystal. P.S. i did this with a level 31 monk so it might be a good idea to play a bit and then go back and do this

Easily obtainable on the first level, "The Gates of Dragonfall".

Set up two Lightning Strike Auras at each enemy spawn. If desired, put a Flame Aura after each set to catch stragglers that are missed.

After Wave 2, remove Flame Auras, if added, grab new gems, and add more LSA's.

Near the end of the second wave (there's no build phase for Wave 3), grab gems and add more LSA's, add two Flame Auras for the middle and right lanes, leave left lane near Crystal open so the boss doesn't die. As long as the boss is alive, new mobs will keep spawning.

Should easily obtain the achievement this way!!

For those that like a video guide.