The Lethal Legion is a criminal alliance dedicated to power, profit and the destruction of the Avengers. It began with Eric Williams, whose brother Simon betrayed the Avengers as Wonder Man but ultimately sacrificed himself to save them from the Masters of Evil. A grief-maddened Eric blamed the Avengers for Simon’s death and became their mortal enemy as the Grim Reaper, eventually joining forces with fellow Avengers foes Living Laser, Man-Ape, Power Man, and Swordsman, as the Lethal Legion, whose members competed with each other to see who could capture or kill the most Avengers. The Legion was soon defeated and imprisoned, thanks largely to the android Vision, a new Avengers recruit whose artificial mind was programmed with a copy of the late Simon’s brain patterns.
As years passed, the Reaper’s ongoing enmity with the Avengers was complicated by his love-hate relationships with both the Vision and a resurrected Wonder Man, neither of whom Eric fully accepted as the “real” Simon Williams. Meanwhile, the Legion regrouped under the leadership of crime lord Count Nefaria, whose associate Professor Sturdy boosted the powers of Legion members Living Laser, Power Man, and the Whirlwind; however, this temporary power boost was actually part of a process that Nefaria soon used to drain the Legion’s power into himself, becoming a near-unstoppable superman. Despite his new power, Nefaria was defeated by the Avengers after a long and desperate battle, and the entire Legion was captured a second time.
Allied with Ultron, Black Talon, Goliath (formerly Power Man), Man-Ape, and Nekra, the Reaper menaced the Avengers again as part of a bizarre scheme to re-create the “real” Simon Williams by transferring portions of the minds of Vision and Wonder Man into a zombie altered to resemble Simon’s original human form. The plan failed and the Reaper-having belatedly realized that Vision and Wonder Man were truly his brothers-fell to his death while fleeing in shame. The rest of the Legion escaped except for Goliath, who was captured yet again. The Reaper would later be reborn as a supernatural menace.
The next Legion arose from a completely different mystical source when the demon lord Satannish stole the souls of infamous killers Lizzie Borden, Josef Stalin, Lucretia Borgia, and Heinrich Himmler from the realm of rival demon lord Mephisto, transforming them into the super-beings Axe of Violence, Coldsteel, Cyana and Zyklon. With the Hangman (a movie star who had sold his soul to Satannish) as their field leader, this Legion was assigned to kill Satannish’s Avengers foes and capture their souls, in exchange for which Satannish would supposedly restore the Legion fully to life. The Legion finally managed to lure the Avengers to Satannish’s realm, but a vengeful Mephisto slipped in with them and fought Satannish for the four stolen souls, all of which were destroyed in the battle. The Avengers escaped, but not before Mockingbird died shielding Hawkeye from Mephisto’s spiteful parting blasts. Satannish himself was later destroyed by Mephisto, but whether Hangman, Nefaria, the Reaper or anyone else will rebuild the Lethal Legion remains to be seen.