Arc Lightning is an evil karma power utilized by Cole MacGrath in Infamous. It is a continuous stream of lightning that is fired from his hands, allowing it to chain off of conductive surfaces and enemies.
At Thug rank, after initially buying the power, Cole is able to release a continuous stream of lightning towards anything that is aimed at until he stops or runs out of battery cores. It requires Cole to complete five evil side missions.
The Outlaw rank upgrade allows Cole to branch out the Arc Lightning to an unlimited amount of targets, so long as they are close enough in the direction that Cole is aiming. It also increases the damage received by enemies that are hit by the Arc Lightning. It is only available after Cole completes ten evil side missions.
The Infamous rank upgrade causes weaker enemies to trigger an electrical explosion upon death. It is only available after fifteen evil side missions are completed.