09-22-2015, 02:21 PM
It adds the energy type to your attack; the nature of the crystals is magical, and so the extra damage is as well. Deep crystal added another 2d6 to your weapon damage, which means that it can be affected by things like criticals and whatnot, since it's not precision damage either. This stuff, being energy damage tacked onto your attack, doesn't get that multiplier, but in return you can spend more points on it to do more damage. Non-elemental damage is just the magical energy, like from the Ultima spell.