Lightning is a naturally occurring element of destruction that can't be stopped. The reason the {Phantasma} was so scared and afraid of Cain when he used the lightning element, is because the lightning element is the bane of all soul-related magic.
The soul is a very delicate entity that can not survive long outside a container, or body. Using soul magic near lightning was like dancing with death. Although Steve and Vincent could also use the lightning element, their level of affinity wasn't as high as Cain's making them less of a threat to J'orntz.
Since J'orntz was cautious of Cain, he decided to use his most powerful spell, {Elemental Control}. Although devils normally could only use one element at a time, the {Phantasma} was a unique exception.
