Hydra as similar ideas to that of the Nazis, which has ethics that were "a racist version of new-Darwinism" (Weikart 195).
One of Hydra's main attributes is that they cannot be killed. Looking at the Greek Hydra, it is a monster with many heads. When you cut off one head, 2 more take its place. This is the motto of Hydra. Overall Hydra is a villain that as many real world roots, including terrorism and the Illuminati.