Hydra is Helion aligned and in direct conflict with the Ethian aligned S.H.I.E.L.D. Hydra aim for nothing less then complete freedom of rule of Earth by humans, their own global domination, and the subjegation, sterilisation, and utilisation of 'sub human' variants and aliens in their new empire.
Baron Strucker (Military Command)
Baron Zemo (Intelligence and Special Operations)
Dr Sivana, leading Hydra's eugenics R&D