The Illusive Man is the leader of the pro-human group, Cerberus. Through Cerberus he attempts to put Humanity at the top of the food chain. He also believes that biotics are the key to human ascension. The Illusive Man uses his private military and several assassins to consolidate his power and put those in power who would serve his goals.
The Illusive Man was created in Mass Effect (video game). He is voiced by Martin Sheen who lends his appearance to the character (albeit de-aged).
Mass Effect: Redemption
In Mass Effect Redemption, the Illusive Man tasks Miranda Lawson to find the body of Commander Shepard.