Hydra Monster Card art by Jeff Reitz

Hydra Culture, Psychology, & Lore

by Vassar Oenbring

“The Hydra was first spotted in Alria Cove early this spring. After it tore into a few of our merchant schooners, the Sail Masters sent mercenaries to trap it in the caves at low tide. The foul creature devoured several of them and refused to die. Now it is more aggressive than ever—our ships sail far out of the trade lanes to avoid it. We can only pray to the Sea-gods that it moves on soon.”

– Seamus Defthands, Idrian Mariner

Culture and Psychology

Hydras inhabit coastlines, swamps, and lakes throughout the world. Although they are natural swimmers and prefer to hunt in water, they are sometimes found on land when motivated by hunger, fear, revenge, or a potential mate.

Few living creatures are safe from the Hydra’s seemingly endless appetite. The territory around new Hydra dens is quickly abandoned by prey animals and sentient beings alike. As a result, Hydras are nomadic and cannot remain in the same region for more than a few months at a time. Groups of Hydras are essentially unknown, as they compete with each other for food and exhaust the prey species in their habitats.

Hydra procreation is a turbulent affair, concluded quickly. Ovulating females announce their intent by excreting a thick foam of pheromones into a body of water. Interested males seek to win their favor by bringing a steady supply of freshly-killed meat. The only reliable observations of fights between Hydras are the result of multiple males attempting to impress a single female. If a suitor is accepted and the mating is successful, the female then repels the male by biting off his heads until he gets the point and leaves.

Female Hydras lay dozens of cask-sized eggs in globulous clusters anchored below the waterline. Mothers frequently remain with their eggs until the hatch, at which point they pile up kills for their young before abandoning them. Hydrlings emerge from their eggs with only one head, but quickly grow another during the first week of life.

Although they attack most creatures on sight, Hydras are not hostile toward each other. They convey simple ideas via hissing and writhing head movements, and may communicate in this fashion for some time upon meeting. Once met, Hydras usually go their separate ways and avoid each other’s territory. Although they rarely join forces for anything, reports exist of two or more Hydras attacking common enemies such as companies of Merfolk, military galleons, or other huge predators that threaten their eggs or food supply.

Hydras are remarkably individualistic and display a bewildering variety of habits. Some have adapted to live primarily on land, so long as they can enter water at intervals. Others show a preference for particular prey: Hydras have been observed preferentially hunting sharks, dolphins, octopuses, Merfolk, bears, moose, Elves, Lizardfolk, and Dragonborn. Most appear to hate fire and fire magic, but a few desert and tropical subspecies seem not to fear it. It appears that aside from a love of water, a fear of Dragon Turtles, and an insatiable longing for raw flesh, Hydras share little in common.

Special Tactics

Ambush and misdirection come naturally to Hydras. They commonly conceal themselves in seaside grottoes, hide in the crevices of reefs, or burrow into sandy shallows to wait for prey to come within reach. This behavior makes them particularly dangerous to fishing boats. Sailors are often unable to detect hiding Hydras before they attack. In the sea, Merfolk report that Hydras use their tails as lures to tempt sharks and other prey within range. On land they frequently leave carcasses or gleaming treasures near their dens to attract scavengers.

When assaulted, Hydras react with indignant rage, and rely on their strength to see them through a melee. Occasionally, Hydras feign retreat in order to attack an enemy from the rear, but they rarely flee battle unless defeat is certain. Similar to Trolls, Hydras are vicious and relentless attackers in large part because of their regenerative ability. They simply do not fear physical damage; their experience has taught them that uncompromising attacks lead to success.

Qualities

Curious. Anything that is not immediately appetizing to a Hydra may pique its curiosity. A preoccupied Hydra suffers Disadvantage to Perception and Initiative rolls while it evaluates an interesting distraction.

Eldritch Mind. Hydras are individualistic and inscrutable in the extreme. All Survival, History, or Insight checks made to discern information about a specific Hydra are made at Disadvantage.

Implacable. Diplomacy, trade, and casual conversation are unknown to Hydras, who generally regard all living beings as food. Even magical means of communication cannot usually compel a Hydra to converse or negotiate.

Territorial. Hydras defend territories that extend for many miles around their lairs. While in the water, Hydras gains Advantage to Perception and Investigation checks to detect and locate other submerged creatures within 1 mile.

Voracious. A Hydra’s appetite is seemingly endless. They will happily devour herds of cattle or even an entire whale if given the opportunity.

Weapons

Melee 1. Tail Whip (Reach 15, 2d12+5 Bludgeoning) A Hydra may substitute Tail Whip for one of its bite attacks. Tail Whip may only target creatures behind the Hydra.

Melee 2. Claws (5d10+5 Slashing) Hydras may forgo their Bite attacks to rear up and attack a single target with their front claws.

Ranged 1. Water Spout (60’ Cone, 5d10 bludgeoning damage, DC 12 DEX save for half damage, DC 12 STR save or be knocked prone) By using a full-round action, a Hydra may use its heads to expel a massive fan of water from its gullet. The Hydra may only use this ability once per long rest.

Ranged 2. Electric Skin (20’ radius from Hydra, 4d8 Electricity damage, DC 12 CON for half) While underwater, a Hydra may use a full-round action to produce an electric shock that emanates out from its skin. This attack does double damage against constructs and elementals.

Special Units

Awakened One. Whether by quirk of fate or strange magic, an Awakened One has INT and WIS increased to 12 and speaks Common, Aquan, and Deep Speech. Awakened Ones are extraordinarily eccentric and will occasionally make bargains with other creatures in pursuit of their own inscrutable ends.

Depth Dweller. Frilled gills adorn these Hydras’ necks, granting them the ability to breath both on land and underwater. A Depth Dweller’s movement is increased by 10 underwater, but decreased by 10 on land.

Hyrdling. Immature Hydras are Large creatures that lack the regenerative capabilities of their elders. They generally have only 2 or 3 heads, have half the hit points of adults, and can move twice as fast.

Primordial. As Hydras have no natural limit to their lifespans, some fearsome specimens achieve truly terrifying size and vigor. Primordials have maximum hit points and +2 to all attacks due to their great strength.

Ti-Hoveder. Hydras that have lost all of their original heads and regrown new ones may now have 10 heads, making them both more perceptive and less focused. Ti-Hoveders have Advantage on Perception and Initiative rolls, but suffer Disadvantage to INT and WIS saving throws.

Special Abilities

Crush. In place of a normal Bite attack, a Hydra head may Crush a Large or smaller creature with its chin instead. Crush deals 1d6+5 Bludgeoning damage and the target must make a DC 15 STR check or be knocked prone.

Revive. When a Hydra regrows 2 or more heads at the end of its turn, each pair of new heads may use a free action to remove one mind-affecting condition affecting the Hydra by nipping at the older heads.

Shred. If a Hydra hits the same target with two or more bites in a single turn, it may make a Grapple attempt against the target as a free action. If the Grapple succeeds, all subsequent Bite attacks against the Grappled target hit automatically until the end of the Hydra’s turn.

Thrash. A Hydra may use a full-round action to flail itself wildly about. Any creature within 15’ of the Hydra takes 10d8 bludgeoning damage, with a DC 12 DEX save for half.

Wail. By uttering an undulating wail as its Attack action, a Hydra may attempt to stun nearby creatures. Any creature within 100’ failing a DC 12 CON save is stunned for one round. The range of this attack is doubled while underwater.

Movement

Run. Good. While not particularly agile, Hydras are fast on land and do not tire quickly.

Climb. Poor. Hydras have sharp claws but unwieldy bodies. They climb when they must, but are not skilled at it.

Swim. Good. Although they lack fins and flippers, Hydras are at home in the water and quite comfortable even at great depths.

Burrow. Poor. Hydras can burrow quickly to hide themselves in sand or mud. They enlarge their lairs by tearing at the earth, but are not otherwise known to dig.

Fly. n/a. Reports of winged Hydras are vanishingly rare. If they exist, they are terrifying monsters indeed.

Grudges

Intelligent sea life fear Hydras above almost all else. Whales, sharks, and giant squid hate Hydras and will flee from them or band together in large battalions to drive them away. Merfolk and Sea Elves view Hydras as instruments of divine punishment, visited upon unfortunate settlements by the Gods of the Sea.

The enmity of such creatures is little more than an annoyance to most Hydras.

Dragon Turtles, however, cause even the most ravenous Hydras to flee into the darkest sea caves and crevices. Dragon Turtles relentlessly pursue and devour unlucky Hydras while shrugging off their frantic attacks with typical turtle stolidity. It is unknown if this behavior is purely dietary or if an ancient grudge exists between the two species. Many island cultures keep oral legends of Dragon Turtles who saved their ancestors from predation by Hydras.

The Troglodytes of Chulg revere Hydras as avatars of Tiamat, and offer sacrifices of slaves and livestock to any Hydras they encounter. This makes Hydras somewhat tolerant of Troglodytes. It makes Troglodytes even less popular than they already are with populations both above and below the waves.

Hydras