HYDRA is a fictional terrorist organization in the Marvel Universe. The organization first appeared in Strange Tales #135. In its original continuity, it was headed by nondescript businessman Arnold Brown, who was killed as S.H.I.E.L.D. apparently crushed the organization. It soon returned, however, headed by Baron Wolfgang von Strucker, under the aegis of the Nazi Red Skull; HYDRA's changing origin was one of the earliest Marvel retcons. After its initial defeat, several of its branches surfaced, appearing to be unrelated and independent. HYDRA's scientific branch was initially A.I.M. (Advanced Idea Mechanics), which later split off into its own organization. Other factions included THEM and the Secret Empire.
Despite the capitalisation, the name is not an acronym, but rather a reference to the mythical Lernaean Hydra. The organization's motto references the myth of the Hydra, proclaiming that if a limb is cut off, two more will take its place, proclaiming their resiliance and growing strength in the face of resistance. HYDRA agents often wear distinctive green garb featuring a serpent motif.
Shortly upon joining the original HYDRA, Von Strucker seized control of the organization from its Japanese founders and slowly steered it towards the goal of conquering Earth. That campaign brought him into conflict with Charles Xavier and the future Magneto among others, and once HYDRA became more brazenly public in its operations, eventually led to the creation of the original agency known as S.H.I.E.L.D. specifically to counter HYDRA's threat to world security. After apparently assassinating S.H.I.E.L.D.'s first executive director, Nick Fury was appointed as executive director. This decision, after several HYDRA campaigns including the creation of the Overkill Horn (designed to detonate all nuclear explosives worldwide), and the bio-engineered "Death-Spore" Bomb, led directly to von Strucker's first death at the hands of Fury and several deceived HYDRA operatives.
In the wake of von Strucker's first death, the surviving elements of HYDRA broke into factions that each adopted its own reorganized modus operandi. Several of these factions developed "super-agents" that would occasionally break away in turn to become freelance operatives, or, in some rarer cases, super-heroes such as the first Spider-Woman. Von Strucker was eventually revived and reunited several of the HYDRA factions under his leadership to renew his campaign against S.H.I.E.L.D. and humanity for several more years.
Despite his reorganization of the group, various independent HYDRA factions continue to operate around the Marvel Universe, and a HYDRA Civil War would later result. While Baron Helmut Zemo had Strucker placed in statis for his own ends, Gorgon and Strucker's second wife Elsbeth von Strucker mystically created a clone of Strucker who they set up to fail, allowing for a public execution of him, after which - as part of an alliance with the Hand, they utilised an army of brainwashed superheroes and supervillains, including Northstar and Elektra to launch a massive assault on SHIELD. The assault was ultimately repelled and Wolverine would kill Gorgon.
Recently, Hydra planned an all out attack on the United States by smuggling missiles into New York for use in a planned bio-weapon assault on the Ogallala Aquifer. They formed a distraction using clones of the Avengers (Iron Man, Captain America, Thor and the currently deceased Hawkeye) but were foiled when Spider-Man joined the Avengers' new line-up.
They also appeared in X-Men Evolution, behind the creation of X23 (Courtesy of Wolverine's DNA).
HYDRA also appears in The Official Movie Game. In the game, HYDRA is partially responsible for the creation of the Master Mold and Sentinel robots alognside William Stryker. Under orders of their leader, Silver Samurai, HYDRA infiltrates Stryker's base to remove all evidence and Sentinel equipment, and by accident, activated the Master Mold.
Fictional cloners | Fictional organized crime groups | Marvel Comics supervillain teams | Marvel Comics organizations