The OMAC (Omni Mind And Community, originally Observational Metahuman Activity Construct) is a type of cyborg who take over human bodies via a cybernetic virus in order to assassinate any and all beings with superpowers. Created by Brother Eye and Maxwell Lord, the virus was created from Brainiac-13-derived nanotechnology acquired by the U.S. Department of Defense and Lexcorp, which was then secretly introduced into general vaccine supplies.
An OMAC unit has access to archives on almost every metahuman on file, and can simulate the powers of a variety of superheroes and supervillains in order to target its opponent's weaknesses. Among the powers displayed were the ability to fly, shoot fire, project needles of artificial cellulose (against Alan Scott; an approximation of his weakness to wood), dispense flame-retarding foam, and fire various energy beams from its eyes and hands with caustic, concussive, or blinding effects. In addition, the OMAC unit can morph its extremities into blades and pincers. It once simulated Shazam's lightning power and forced Mary Marvel to revert to her human form. It can disable the Eradicator effortlessly.
The only weakness an OMAC has is that they are human beneath their shells (which was meant as a deterrent to heroes using lethal force against them). Other than that, the OMACs are dependent on their assessment of individual heroes. When fighting multiple opponents, they require a few seconds to adapt their countermeasures for each hero. OMACs are also vulnerable to Mister Terrific, as he cannot be detected by technology
During the technology's creation, the first test subject activated was a human called Buddy Blank. Equus and Pilates, are later denounced as supposed former iterations of the OMAC concept; and an mechanical OMAC is featured as an enemy for the Metal Men.
While initially only activating the cyborgs as the need arose, Brother MK I, rechristening itself Brother Eye, initiated the "KingIsDead" protocol after Mawell Lord was killed by Wonder Woman. This protocal activated all 1,373,462 OMACs to attack and kill all the metahumans on Earth. A group superhero effort stopped the attack, reducing the number of OMACs to roughly 200,000 by disabling the majority of them with an EMP blast as well as a "Shut Down" command given by Sasha Bordeaux, who had become a third-generation cyborg linked to Brother Eye, now designated Blacknight 1. These measures effectively freed the OMAC hosts from their nanotech forms.
After this, Brother Eye attempted to besmerch Wonder Woman's name and initiated the final protocol, "Truth and Justice," by having all the remaining OMACs invade and attack Themyscira to wipe out all of the Amazons.
With the destruction of Brother Eye, despite its attempt to reboot inside the body of Blackknight 1, the remaining OMAC units were deactivated and reverted back to their human hosts.
A surviving Brother Eye fragment in NORAD, activates one final OMAC unit, Michael Costner, as the last OMAC unit, however it, too, is destroyed when Costner regains control of himself. However, Brother Eye, again, survived.
As time went one, Brother Eye wielded its OMAC units as its foot soldiers, becoming involved in and assisting in the war against Darkseid.
With Maxwell Lord's return to the living, a new series of OMACs have appeared.
An OMAC created using Brother Eye's limited remaining nanotech virus as a means to defend its damaged systems, this unit was created using two Israeli civilians who happened to stumble upon the down satellite. The unit remained with the satellite, aggressively defending it against attacks from Russia, China and Israel as the unit Blackknight 1 was summoned to make contact. This unit was deactivated following the final destruction of the satellite it was protecting, the hosts did not survive.
A third-generation OMAC unit, Checkmate operative Sasha Bordeaux was infected by Brother Eye, unbeknownst to herself or Maxwell Lord, to become an emergency back-up platform should the satellite platform be destroyed. Activated as part of the "Lazarus Protocol", Blackknight 1 would meet with the remainder of Brother Eye and allow it to upload its command-and-control data into her body, becoming redesignated as Brother MK II. However ,Sasha resisted Brother Eye's attempts and ultimately destroyed Brother Eye's remaining systems before it uploaded itself into her. While she freed herself from Brother Eye's control, she was unable to free herself from her nanotech infection and now lives as a part-human/part-OMAC cyborg hybrid.
ReMAC is a modified OMAC leftover from the original OMAC Project. Upon its discovery, Batman claims the unit for his own perpuses, having Dr. Francine Langstrom create a decoy unit to leave in care of the Justice League.
Aptly renamed ReMAC, the unit appears to be a blank cyborg with no set programming. This enables the Outsider's to use ReMAC to their own ends as an infiltrator, using its advanced shapeshifting abilities and its unquestioning obedience.
Batman, Langstrom and Salah Miandad later create a telepresence system, turning ReMAC into an advanced drone for Salah Miandad to control, enabling him to personally operate the OMAC unit.
However, while testing a new neural interface, Salah is knocked into a coma. His mind coming to reside in ReMAC, however, due to the machinations of Simon Hurt, ReMAC is fed a malicious self-destruct code that blows it and the Outsiders headquarters, apart.