A foe's only chance is to sever all the monsters heads in quick succession - if even a single one remains, the remainder will swiftly grow back and devour the impudent attacker for his troubles. They are even more difficult to slay, for not only are their scaly bodies incredibly well armoured, they also regenerate damage at a frightening rate.
War Hydras are notoriously difficult for their handlers to control, and a Beastmaster must be quick with his lash lest he be devoured in the enemy's stead. Those that march on regardless do so either out of confidence in their battle-prowess or ignorance of the Hydra's savagery. Indeed, so ferocious is the Hydra that campaigning armies often make wide detours to avoid intruding on such a beast's bone-strewn lair. The Hydra is a titanic beast of the mountains, whose ill-tempered and ravenous nature has proven the doom of many an unsuspecting morsel.