The Fearsome Five first formed following the placement of an ad in the Underworld Star, an underground newspaper run for criminals. Dr Light invited rogues to join him in attacking the Teen Titans. Four criminals answered the ad: Psimon, Shimmer, Mammoth and Gizmo. With Dr Light as leader, they formed the first iteration of the Fearsome Five.
The Fearsome Five were created by Marv Wolfman and George Pérez. they made their first appearance in The New Teen Titans #3.
Throughout the Bronze Age the team underwent occasional roster and frequent leadership changes. Typically leadership alternated between Dr Light and Psimon. During the Bronze Age they were joined by Neutron, who left soon after, and by Jinx, who remained. At various points Dr Light and Psimon were expelled from the group.
In the Modern Age, the original iteration of the team attracted Charger and Deuce in place of Psimon and Dr Light. Shortly thereafter the team was disbanded for some time before being drawn back together by Doctor Sivana. This iteration of the team consisted of Psimon, Shimmer, Mammoth, Gizmo, Sabbac and Jinx. Following Gizmo's death the team retained the name but did not attempt to replace him. After the Final Crisis the team was reconstituted by Calculator, and consisted of Mammoth, Shimmer, Jinx, Nano and Rumble.
The members of the original team appear as recruits to the Secret Society of Super Villains, however it is unclear if they remain as the Fearsome Five within that group, or whether their origin has changed. This iteration of the team tentatively consists of Psimon, Gizmo, Jinx, Mammoth and Shimmer.
Major Story Arcs
Psimon wrests control from Dr Light and leads the team in attacking the Teen Titans and attempting to brainwash them into attacking the Justice League, which fails. The team later attack the Titans to recover Psimon, who has been sent to an alternate dimension by Trigon because of his continued failure to destroy the Earth. They succeed in rescuing him, but are captured and imprisoned. They continue to commit various crimes, bringing them up against different heroes, and are defeated each time.
Five by Five
Doctor Sivana breaks several imprisoned team members out of jail, restores Shimmer to life, and convinces Psimon to join them. The team attempts to short sell LexCorp stock by stealing account details and murdering everybody in LexCorp buildings. The original Five demand that they attack a nuclear missile facility, but Doctor Sivana refuses. When pressed, he shoots Gizmo in the head and abandons the rest of the team. They attack the facility anyways, and nearly succeed in directing a nuclear attack against Canada. They are stopped by the Outsiders. Mammoth is captured and returned to Alcatraz, but the remaining members manage to escape.
The Five, now technically Four, join up with the Secret Society of Super Villains. They are sent after Pariah, who they manage to capture.
Members of the Five are among the villains who are sent to the planet Salvation. They do not appear to share any great loyalty to one another, as they do not side together or attempt to defend one another when attacked.
Members of what appears to be the team are invited to join the Crime Syndicate's Secret Society of Super Villains. They do so, and are sent after the Rogues. They are trapped in a mirror alongside several other villains and shattered.
Teen Titans Go!
The Teen Titans animated versions of several characters appear in issue #43 of the comic book adaptation. Psimon and Dr Light gather Mammoth, Gizmo, and Jinx to form a new Fearsome Five with which to attack the Titans.
A team based on the Fearsome Five appears in the episode "Beneath," working for the Light. Lead by Psimon, the team consists of Shimmer, Mammoth, Devastation and Icicle Jr.
DC Universe Online
The Fearsome Five appear as part of the "Sons of Trigon" downloadable content. The team consists of Dr Light, Gizmo, Jinx, Mammoth and Psimon.