“The dark side of the Force is a pathway to many abilities some consider to be unnatural.“―Sheev Palpatine
The dark side of the Force was an aspect of the Force. Individuals who used the dark side drew their power from darker emotions such as fear, anger, hatred, and aggression. The Sith were a major practitioner of the dark side, and were the mortal enemies of the Jedi Order, which followed the light side of the Force. There were others such as the Inquisitorius, who, though not Sith, could draw upon the power of the dark side.
If the presence of the dark side was significantly powerful, nearby Force-sensitives could feel cold, such as when Darth Vader was near Ezra Bridger and Kanan Jarrus, or when Luke sensed the dark side emanating from the Cave of Evil onDagobah.
Although Jedi were taught to follow the light side of the Force, the dark side was considered seductive and a Jedi had to maintain vigilance in order to avoid falling to the dark side. Anakin Skywalker was a powerful Jedi who, partly through the machinations of the Sith Lord Sidious, fell from the light side and began practicing the dark side. Even a Jedi raised in the traditions of the Jedi Order from birth could quickly be corrupted by the lure of the dark side in certain situations. Despite this, while the Jedi often described the dark side as a “quick and easy path,” drawing upon the power of the dark side did not necessarily come with ease or without cost to those who were not used to drawing upon feelings such as hatred and who possessed strong compassion.