- "It is a technique that is almost as old as the Sith themselves…it is a means of severing connections between life, the Force, and feeding upon the death it causes. It cannot be taught…it can only be gained through instinct, through experiencing its effects, first-hand."
- — Kreia
Force drain refers to a spectrum of offensive and defensive Force powers, tied to the same concept, which used the dark side of the Force to tap into the strengths of an organic target. Mastery of each technique could scale the area of effect, sometimes dramatically, or exhaust the victims almost instantaneously.
- "As much as one may use the Force to bolster the wills and strengths of others, the reverse is possible, though not often used. Instead of sending one's will through connections in the Force, instead such connections are drawn upon, fed upon, and drained completely."
- — Kreia
Force abilities such as drain life and dark healing siphoned vitality to sometimes offer an equivalent effect of Force Healing, the difference being that the regenerative processes in the user was fueled by draining the targets. Other techniques like Drain Force rekindled Force energy in the user, offensively draining the Force energy from those whom the power was turned upon, or defensively draining the force from certain Force powers. For example, the Sith-trained Dark Jedi Velok was able to use this technique to intercept and absorb Force Lightning. Some wielders of the Force were known to be able to drain life energy and force energy simultaneously, like the Dark Lord Darth Malak did in the last battle of the Jedi Civil War as he dueled his former Sith Master Revan. He used Force Drain to draw upon the power of captive Jedi who had fallen in the attack on Dantooine.
As detrimental as the teachings of the dark side were said to be to the very flesh of their practitioners, Force Drain could be more dangerous still, if one relied on the technique or did not contain its full measure of power. During the First Jedi Purge, in his hunger for power, the Sith Lord Darth Nihilus honed a pernicious means of feeding upon the Force, which eventually enslaved him. The arcane practice was known to the ancient Sith and came into use at some point after the Hundred-Year Darkness. It was lost over time, however, as the Lords of the Sith abandoned Republic space and their strongholds were deserted. According to Kreia, the technique itself could not be taught but only be gained through instinct, through experiencing its effects first-hand, which was possibly an irreversible process as the absence left in the victim turned into hunger, eventually compelling them to feed themselves.
Kreia described this ability as a means of destroying connections between life around oneself, drawing upon them until they were drained completely and the exhausted life died. Nihilus supposedly took this practice to unmatched levels; wiping out entire planets, he became something of a hole in the Force, his mere presence killing all around him, slowly, feeding him. Wounds in the Force located in places such as the dark side world of Malachor V were said to bear a similar behavior.
The most grandiose display of Force drain was given by Nihilus when he consumed Katarr, a Miraluka world in the Mid Rim. However, unchecked use of his talent took the form of addiction, and would have ultimately cost his life had he not been slain by the Exile. The hunger that possessed him would have kept growing, along with his power and his reach in the Force, posing a threat to all life. Other examples are Exar Kun, the Dark Lord in the time of the Great Sith War, who harnessed Sith and Jedi artifacts on Yavin 4 to enhance his power and drain the entire Massassi species, so that his spirit could endure for more than four thousands of years in the Great Temple; and Galactic Emperor Palpatine, who fed off the inhabitants of his retreat world of Byss collectively with his dark side adepts, although those unfortunates were drained slowly, over a long period of time, rather than consuming the whole world at once.