Formed by Jaron Namir at an unknown time, they work in secret for the Illuminati, performing clandestine operations without question or hesitation. D-Bar explains that they are similar to the Icarus Effect, a social phenomenon where, to maintain "stability", society eliminates individuals who excel too far, before the public is ready to accept radical advancement. In the Tyrants' case, they either coerce, intimidate, or kill anyone involved in the spread and advancement of mechanical augmentation, as it presents a challenge to the total power and rule the Illuminati hold.
They are named after the Latin word "Tyrannus", meaning "One who takes control with their own actions". Although in some cases, the Tyrants are asked to operate in secret, for more important operations they may openly kill people in public, and the Illuminati will use their influence to cover it up. Some examples are the assassination of Caidin Global CEO Garret Dansky, which was framed on the Red Arrow Triad, and the slaughter of Secret Service agent Ron Temple along with many of his friends in his own home, which was blamed on Secret Service Agent Anna Kelso. The Tyrants are paid handsomely, have access to cutting-edge weapons and augmentations, and have their own private airplane. In their line of work, the Tyrants must all execute their orders without hesitation or question, even when it involves killing civilians in cold blood.
Only the leader of the group, Jaron Namir, can actually communicate with their superiors, and then only through the Killing Floor, an online construct which stores small, unusable amounts of data across thousands of different drives. Because of this, it is nearly impossible to locate and use any data without legitimately logging in with the true password. Before joining the Tyrants, most of the persons' close contacts and relatives are killed off, to remove most aspects of social life. The only exception to this rule is, supposedly, Namir, who has a wife and children.
By the end of Deus Ex: Human Revolution, the Tyrants have been eliminated, either killed in action or resigned. There may be other groups of similar intent under the Illuminati's control, however.
Jaron Namir (call sign "Silver") - Leader of the group, Jaron gives mission objectives to the other members and leads most operations. He possesses an augmented musculature system and right retinal prosthesis. Jaron somehow manages a double life, both as a black ops soldier and as a peaceful family man at home. He is killed by Adam Jensen under the Omega Ranch in Singapore.
Lawrence Barrett (call sign "Blue") - Born in Missouri, USA, Lawrence is a very tall, muscular man with two artificial arms. During a fight with Ben Saxon, several concussion grenades around his belt detonated, severely scarring him. He is later killed by Adam Jensen under Highland Park.
Yelena Fedorova (call sign "Red") - An African-Russian woman who rarely speaks, Yelena has two augmented legs and a cloaking system. She is capable of speaking, but chooses not to. She initiated a brief affair with Ben Saxon after his initiation into the Tyrants. She is later killed by Adam Jensen in the basement of Picus Communications.
Gunther Hermann (call sign "Green") - A former member of the German Counter-Terrorism unit GSG-9, Gunther felt restricted by the extensive government supervision the job required, and he was recruited by the Tyrants in exchange for past troubles going away. He is a ruthless killer, feeling no regret after slaughtering several civilians. He only owns a single prosthetic arm, though he wishes to augment himself as extensively as possible. He is physically diminished by an explosion, but is augmented into operative state by the Illuminati and Majestic 12. Many years later he is defeated by JC Denton in the underground cellars of the Cathedrale de Payens.
Scott Hardesty (call sign "White") - The group's sniper. A former agent in the CIA, Scott felt close to Joe Wexler, though at the same time he is very skeptical of new recruits. He and Saxon clash, as he believes Saxon is too weak to be a Tyrant. Is killed by Ben Saxon in Geneva, Switzerland.
Joe Wexler - A former member of the CIA, Wexler got recruited after the death of his wife at the Tyrants hands. He was involved in the assassination of Garret Dansky, but was killed by Anna Kelso in Washington D.C. His death was most likely why Ben Saxon was recruited for the Tyrants.
Ben Saxon (call sign "Gray") - Ben first worked for the British SAS, and then worked for Belltower Associates, a private military company after leaving the service. During an operation during the Australian Civil War, his own group, Strike Team Six, were all killed due to misinformation by his superiors. After recovering from his injuries, he joined the Tyrants to find those responsible for his team's death. Leaves the Tyrants after finding out they killed his team. Jaron Namir clearly stated that Saxon was recruited because of his code of honor and the balance it would apply to the Tyrants.