Deadly Sight was a power of the dark side of the Force that harnessed a Force-user's fury and hatred and then projected them through an intense glare onto the victim. It would blister the skin and vaporize extremities.
While it was once an extremely rare ability, even among the Sith, the usage of this ability exploded in the last decades of the New Sith Wars. The Jedi Order considered it forbidden for use by Jedi Knights.
A stormtrooper being dissolved by Deadly Sight
Darksiders could inflict pain and injury upon their foes merely by looking at them, causing victims' bodies to burn and smoke as they died. The user of Deadly Sight could damage entire groups of foes within their field of vision. Deadly Sight injured everyone that the user looked at, including allies and civilians; it is unknown whether it could be refined, especially because of its dark nature.
Tiring to sustain, it was inefficient in terms of the strain caused on the user's Force reserves, but was nevertheless effective in the right situation.
The only known practitioner of Deadly Sight after the Rule of Two was established was the Dark Jedi Sariss, who used it in her duel with Kyle Katarn in 5 ABY.
- The Jedi Path: A Manual for Students of the Force
- Star Wars: The Card Game — Knowledge and Defense