HYDRA from Marvel comics
During the earliest recorded days of human history, a group of Egyptians, led by a man named Imhotep, fought back a Brood invasion. Spurred by this, the survivors formed two secret organizations - the Brotherhood of the Shield and the Brotherhood of the Spear. The Brotherhood of the Spear spread out, ingraining itself into all facets of human society - science, magic, politics - like a multi-headed beast, apparently destroyed around the time of the French Revolution. And although it went by many names - the Cathari sect, the Thule Society and all its antecedents - it is under the name of the many-headed Hydra that it is most well-known.
Reformation and efforts
Formed during World War II, Hydra originally had a State Shinto Imperialist as its Supreme Hydra. Baron Strucker slew and replaced this man, but Captain Savage and the Leatherneck Raiders thwarted Strucker's attempt to gain an A-Bomb. Hydra then clashed with the Invaders. Earlier, Strucker had uncovered Gnobian advanced technology, while he also time traveled to the future from 1942.
Aries organized Strucker, the Fury brothers and others into a loose partnership known as the Great Wheel. The tasks he sent this group on led directly to the formation of S.H.I.E.L.D., Hydra, and Leviathan. Hydra's history is a long, tumultuous and convoluted one, spanning the decades from the end of the World War II up to the present day, tied directly to surviving fugitive members of governments of Nazi Germany and Imperial Japan.
Soon after the formation of S.H.I.E.L.D., one of its members and a former member of the Great Wheel known as the Professor secretly betrayed the organization to Hydra and became a double agent. Strucker used this connection to make Hydra the secret master of S.H.I.E.L.D. and thus Nick Fury. Hydra used S.H.I.E.L.D. as part of a years-long, slow burning plan to subvert the entire world and bring it under their control.
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 agency known as S.H.I.E.L.D. The S.H.I.E.L.D. was formed by Hydra proxies in the United Nations specifically to gain power and information in ways that Hydra never could from its position then. After the apparent assassination of 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, superheroes 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 stasis 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 utilized 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.
Edgar Lascombe took over as leader and under his command, 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. Lascombe know the reason why Hydra had failed so many times, was the lack of superpowers, so they formed a distraction using clones of the Avengers (Tactical Force instead of Iron Man, Militant as Captain America, Hammer as Thor and Bowman as Hawkeye, who was dead at the time) but were foiled when Spider-Man joined the Avengers' new line-up.