Quote Originally Posted by Abizzle
You can get the energy crystals from the ruby dragons, by stealing with the rare item ability{without if ur lucky from Elnoyle in Esthar on the bridge that goes through the center by talking to the crazed man. You can also get it by modifying ruby dragon cards. Laser cannons u can steal from Robotic soldiers with wings in the d district prison, and also from those flying four legged machines in the lunatic pandora{the ones that flail thier limbs when they get low on hp. ill have to hit u back on the power generator.
You don't have to mug the Elnoyle you fight in Esthar. Just defeat it, and it drops an energy crystal, or two. That's why many people have already suggested ways to kill it quickly.

From my experiences, Ruby Dragons RARELY drop energy crystals.