- "Some possess raw elemental power; they can unleash storms of lightning from their fingertips…"
- — Darth Bane
Force Lightning is a purely energy-based attack used by practitioners of the Dark Side, especially the Sith. Because of this association, the ability is also commonly referred to as Sith Lightning. The attack channels Force energy down the user's limbs, hurling arcing bolts of electricity from the wielder's fingertips or palms; Force lightning can be executed with either one or two hands. Powerful discharges will branch out into dozens of smaller forks; thus, skilled practitioners can target several foes at once.
This power has also been widely used as a form of torture, as it causes not only severe physical damage but also unbearable agony to the victim's emotions and spirit. However, a single powerful blast may be sufficient to kill a person instantly.
The intensity of this power varies based on a number of factors, but a skilled user can render a target unconscious with only a short burst. Depending on the level of intensity, Force Lightning can ground itself on an ignited lightsaber. Powerful Lightsiders are sometimes able to resist the attack, or even block the lightning completely.
Because Force Lightning requires a living conduit for the energy to be channeled, Darksiders like Darth Vader were never able to employ this power, as all his limbs were prosthetics.
It has also been demonstrated, by the Darksider Sivter, that Force lightning can actually be controlled to an extent. Sivter has proven on many occasions that he can direct where his lightning goes. Instead of firing it directly in front of him as others do, he can change its path while its being fired. No other Darksider has shown this level of control and it is thought to be an ability he developed; unique to him.
Though the short-term effects of Force lightning are obvious, the sheer power invoked by its use can have insidious long-term effects, both on those subjected to its power and those who would wield it. Prolonged exposure to intense electrical fields (such as a sustained current of Force Lightning) causes most humanoids to experience sudden and massive calcification of their skeletal system; the abrupt drop in blood minerals provokes muscular microseizures all over the victim's body. Telltale symptoms included generalized muscle aches and double vision. A blood test or bioscan can be used to confirm the diagnosis. Unless the victim receives complete bed rest and appropriate medical treatment, the disorder can become chronic, lingering for years (barring timely bacta immersion).
For the user, Force Lightning can be very draining to their energy since it is expelled with such quantity and power. It also has the added drawback of occasionally charring the hand of the person who has used it. This is generally only seen in untested users of this ability, those who have mastered it aren't known to suffer burns.
Very powerful blasts of Force Lightning can highlight and illuminate the victim's skeleton.