A villain in the DC Universe. First appeared in Flash (second series) #3.
In its own words, the Kilg%re is an "electro-mechano-organic life form", that requires "electro-life force" to survive. It lives in circuitry and power systems, and can control any mechanical or electrical devices connected to the systems it inhabits.
The Kilg%re originated in a planet in the Pleiades cluster, but was forced to launch into space after consuming all the energy in its home planet. Then, after some sort of conflict with an entity known as Meta#sker it was trapped on Earth, out of phase with the rest of the world and only perceivable at great speed.
When the Flash was running time trials in the Utah desert, Kilg%re was able to use his speed to pull itself back into phase. It then quickly took control of the computer systems running the nearby S.T.A.R. lab, and from there entered and took control of the national power grid. Kilg%re decided that humans were a threat to its existence, and demanded that all humans leave North America or face elimination.
Kilg%re was defeated then by shutting down all power around the world, robbing it of the electricity it needs to survive. This defeat was merely a setback for the Kilg%re, which had retreated into a computer created by Metron of the New Gods and hidden underground to monitor human progress. Kilg%re learned to be more cautious, dispensed with the idea of eliminating humans, and decided instead that the best way of protecting itself was to lay low while promoting international stability.
To this end, Kilg%re started exerting an influence (through Metron's computer) on wealthy businessman Maxwell Lord IV. Together, Kilg%re and Lord manipulated events to get the Justice League official United Nations support, and the League became Justice League International, with Lord as its leader and UN liaison.
Kilg%re's influence on the League and Lord was eventually discovered, and (after it was defeated in an attempt to take over Supertown on New Genesis) it again retreated into the world's computer systems, where it has resided since.
Kilg%re has emerged only a few times since then. Once, it staged a fake final battle to convince the world of its demise (although the Flash saw through this ruse, and was rewarded with a device that would later restore him to life after a fatal wound at the hands of Vandal Savage), and it also gave Maxwell Lord a final chance at life, as the villainous Lord Havok.