Issue #1, May 2011
In January 2011, Paragon killed the other members of the Justifiers and began a mass murdering rampage, destroying parts of Atlanta and Chicago, sinking Singapore into the Pacific Ocean, and killing hundreds of individuals including the Vice President of the United States. In April 2011, Paragon was stopped by the legacy heroes who would then become the new Justifiers.
In the aftermath of Paragon's crimes, a wave of retribution against posthumans began. Worldwide, anti-posthuman demonstrations and violence became common. Unfortunately, with the majority of superheroes being either dead (by Paragon's hand) or unavailable, the number of criminal acts committed by posthumans rose sharply. In addition, a significant number of incarcerated posthuman criminals were due for parole or outright release.
Anticipating that the situation could quickly get out of control, the U.S. Government took steps to set up Citadel to protect people from posthuman criminal activity and to restore some of humanity's faith in the posthumans among us.