Hydra has a long history. In ancient Egypt, the brilliant deeds of the Egyptian wizard Yin Hetan (the bald villain in the mummy series) against the apocalypse inspired the survivors. According to Yin Hetan's weapons, spears and shields, two secret organizations were established, namely the Holy Shield Brotherhood and the Holy Spear Brotherhood. Needless to say, the shield evolved into a shield, and the spear evolved into a hydra.
Hydra has many opportunities to make public appearances in the Marvel universe. From the story timeline to the comic creation timeline, it has been tossed for more than half a century. Opponents include Captain America, Nick Frey, his Howling Commando, Wolverine, Spider-Man, Hulk and others, who literally can't kill Xiao Qiang. Among them, the personnel organization is quite complicated, and the Red Skull is at most a participant and an indirect founder.
Hydra's famous saying: Cut off one head and two heads will come out.
Hydra's * * * is also this virtue. There are always various leaders, and sometimes there are internal divisions. Well-known leaders are Lady Hydra and Baron Cedric. He is the guy with a monocle in the movie Captain America 2.