The Hydras depicted in Defenders of Earth are monsters hostile to Earth and seek to eradicate humanity. They are usually pitted up against dragons such as Firroth and or are allies of dragons such as Vezoth.
In addition, the Hydras are the only characters made by the wiki founder alongside the Dragons, the Mutant reptiles and the Dinosaurs as well as the animals depicted in The Mammal Wars to be trans wiki articles as they also appear on the second untermation wiki.
Legend of the Hydra
The original Hydra known as the Lernean Hydra was a monster in Greek mythology that had eight heads and possessed the ability to regenerate. Whenever one of its heads was cut off, two more grew back.
In the legend, Eurystheus, king of Tiryns, sent the demigod Heracles to slay the Lernaean Hydra as the second of the set of labours that the hero had to complete, in order to redeem himself for killing his wife Megara and his children in a fit of madness. When Heracles reached the lake Lerna, he had to cover his nose and mouth with a cloth, in order to protect himself from poisonous gases that were emitted. After he managed to lure the monster out of its lair, Heracles quickly cut one of its heads off, only to realise in despair that two new heads had grown.
So, he decided to ask for the help of his nephew Iolaus, who thought of using fire to cauterise the stump as soon as the head is cut off. So, they made a plan; Heracles would cut off the heads and Iolaus would burn the wound with a firebrand.
In Defenders of Earth, the Hydras are depicted as hostile reptiles of extra-terrestrial origin and are much the same as their Earth counterparts from Greek mythology. The only difference is the amount of heads as they possess a minimum of three heads and a maximum of eight; depending on the individual, much of the Hydras also possess the ability of flight while still retaining their abilities of poisonous blood and regeneration.
This in turn makes them one of Firroth's most difficult opponents to defeat because not only do the Hydras grow two more heads, but also two more brains with them and it is this increase in brains that gives them a greater advantage in battle as they have quicker reaction times.
Even though the Hydras are already hostile to humanity, they pose a much greater threat to Firroth and his allies in Dragons and Hydras when the Hydra Krizoumia comes to Earth after being summoned by Nelarth, Lord of the Black. The dragon warlord in turn promises him and his forces that if the Hydras fight along with the Demon Empire, they will have the chance to rule the world along with the Empire should they win the Reptile Wars.