Bloodlust was a quasi-hereditary mental and physical disorder suffered by various members of the Sith species. It caused its victims, when in a state of heightened emotional stress, to lose control of their actions and attack any living thing in the vicinity, friend or foe. Bloodlust could allow its sufferers to act to the full extent of their physical and Force powers and shrug off almost any amount of pain, turning them into destructive dynamos. The lack of any self-control, however, could also doom them, as they had no sense of caution or discretion.
Onsets of bloodlust were usually triggered by sudden and extreme grief, rage, or despair. Most sufferers sought ardently to control the outbursts, and a measure of control was possible with mental training and use of the Force for calming purposes. This latter tended to prove difficult, however, as the disease was specific to Sith and part-Sith, who tended to affiliate with the dark side of the Force and therefore avoided calming and passive mental exercises as a matter of principle.
Very few sufferers went entirely to the other end of the spectrum, but one such Sith was Khrado Sakaros. Rather than make any attempt to control his bloodlust, he embraced it as an ultra-powerful variant of Force rage. While he sacrificed the ability to plan or consciously calculate moves, his Force power was so great that this rarely mattered, and he could use the Force or even duel with a lightsaber purely on instinct.
Bloodlust could appear to develop spontaneously in a Sith when no close relatives had it, but nearly all cases were hereditary, and in the time of the Sith Empire, theorists suggested the gene could lie dormant for generations, even over centuries, before reactivating. While study of a patient actively in a state of bloodlust was obviously extremely difficult and dangerous, many concluded that bloodlust worked by the Force acting on the nervous system of the victim.
Though isolated cases were reported of female Sith suffering bloodlust, the vast majority of victims were male.
List of known sufferers[]
Behind the scenes[]
Bloodlust is in part based on the real-life concept of berserkergang, the state of frenzy (and ensuing indiscriminate slaughter) achieved by Viking berserkers.