Seth Voelker was a Roxxon financial analyst who was surgically implanted with a small device which would permit him to mentally activate the dimensional aperture opening circuitry incorporated in his cloak, thus becoming Sidewinder. He began as part of the third Serpent Squad, but later created the Serpent Society, a team offering the guarantee of never be kept in jail thanks to Sidewinder's teleportation.
Viper infiltrates her own snake-themed men into the Serpent Society and takes over as leader, poisoning Sidewinder and those members still loyal to him. Diamondback escapes and takes Sidewinder with her, using his cape circuits to teleport away and get the Captain's help against Viper. Sidewinder is carried by an ambulance, where Black Racer tries to kill him, but Vagabond saves him.
When Diamondback is captured by the new Captain America, a recovered Sidewinder frees her, and agrees to also free the Captain's friends as they helped overthrow Viper's coup.
Sidewinder grows disenchanted with the Serpent Society after the whole Viper fiasco, and eventually retires, leaving Cobra in command of the Serpent Society.