Appearances in Resident Evil
Resident Evil 5
The Hydra shotgun makes its first appearance in Resident Evil 5. Should the player fully upgrade the starting Ithaca 37 shotgun, the Hydra is then made available for purchase.
Its notable qualities when put against the other shotguns is its effective ratio between power and rate of fire. It has a decent amount of spread as well due to its nature as a triple-barreled shotgun. It is wielded with one-hand by male characters, though female characters still wield it with two like the other shotguns.
In the unlockable Mercenaries minigame, Albert Wesker while wearing his S.T.A.R.S. outfit has it available, as does Chris Redfield in his DLC Warrior outfit for the DLC Mercenaries Reunion mode.
Resident Evil: The Mercenaries 3D
The Hydra shotgun returns as apart of Albert Wesker's Mercenaries repertoire once more and retains all of the same qualities as it had in Resident Evil 5.
Resident Evil: Revelations
The Hydra also makes a reprisal in Revelations. For the story it is unlocked for use upon completing the game and functions exactly as it did in RE5, though like all weapons it can be procured in Raid mode with a number of varying stats as well.
There also exists a special Legendary variant of the Hydra called a 'Drake', which is typically more powerful than the standard Hydra. The Drake variant can only be acquired in Raid mode, however.
Resident Evil 6
The Hydra shotgun in Resident Evil 6 differs greatly from its previous appearances as it is only available for Helena Harper, who comes equipped with it from the very start. Loaded with up to three shots, the Hydra is able to unload all three of its shells as fast as the player can press the firing button. When used with the Quick Shot ability, Helena may also sometimes do a kind of stunt roll and shoot from that position.
Resident Evil: Revelations 2
The Hydra returns to its classic form in Revelations 2. However as all character models now share the same animation sets, all characters--both male and female--wield it with two hands.