Poseidon — Lord of the Sea, Earth-Shaker and Horse-Father
Hellenic Olympian · Sea · Storms · Earthquakes · Horses · Navigation · Trident
Poseidon is one of the great Olympian powers: brother of Zeus and Hades, lord of the sea, sender of earthquakes and divine master of horses. Sailors ask him for safe passage, rulers fear his anger at harbours and walls, and heroes learn quickly that offending him can turn an entire voyage into a war against the ocean.
Read the voyage behind the divine feud: The Odyssey and a recommended edition follow Odysseus through hostile seas, strange islands and the struggle to reach home.
Poseidon at a Glance
| Tradition | Hellenic |
|---|---|
| Divine role | Sea, storms, earthquakes, horses, navigation, coastal power and maritime kingship |
| Game alignment | Chaotic Neutral |
| Suggested domains | Tempest, Nature, War |
| Sacred signs | Tridents, horses, dolphins, bulls, sudden breakers, salt spray and tremors beneath stone |
| Parents | Cronus and Rhea |
| Siblings | Zeus, Hades, Hera, Demeter and Hestia |
| Consort | Amphitrite |
| Divine seat | The sea-realms of Arborea, linked to the Olympian Glades and the waters surrounding the divine isles |
Divine Mechanics
Encounter role: Greater-deity controller / bruiser. Each edition is standalone; use only the tab for your ruleset.
Poseidon, Greater Deity — Large Celestial, Chaotic Neutral; suggested CR 34.
| Armor Class | 27 | Hit Points | 720 |
|---|---|---|---|
| Speed | 60 ft., swim 240 ft. | Proficiency Bonus | +9 |
| STR | 30 (+10) | DEX | 24 (+7) |
| CON | 30 (+10) | INT | 24 (+7) |
| WIS | 28 (+9) | CHA | 30 (+10) |
Saving Throws Str +19, Con +19, Wis +18, Cha +19. Damage Resistances cold, lightning, thunder. Damage Immunities bludgeoning, piercing and slashing from nonmagical attacks. Condition Immunities charmed, frightened, prone. Senses truesight 300 ft., passive Perception 28. Languages all languages he chooses, telepathy 300 ft.
Legendary Resistance (5/Day). If Poseidon fails a saving throw, he can choose to succeed instead.
Lord of the Waters. Poseidon can breathe air and water, ignores difficult terrain caused by water, and cannot be unwillingly moved while touching a natural body of water. Water within 300 feet obeys him unless controlled by another deity of equal or greater power.
Earth-Shaker. When Poseidon deals damage to a structure, vehicle or fortification, the damage is doubled. Creatures standing on natural ground within 120 feet have disadvantage on checks and saves made to resist being knocked Prone by him.
Multiattack. Poseidon makes three Trident of the Deep attacks: +19 to hit, reach 20 ft.; 32 (4d10 + 10) piercing plus 22 (4d10) lightning damage.
Tidal Cataclysm (Recharge 5–6). Poseidon sends a wall of seawater through a 120-foot cone. Creatures make a DC 27 Strength saving throw, taking 66 (12d10) bludgeoning damage and being pushed up to 60 feet and knocked Prone on a failure, or half damage with no push on a success.
Earthquake Stroke (1/Day). Poseidon strikes the ground with his trident. For 1 minute, a 150-foot-radius area functions as violently unstable ground. Creatures of his choice entering or starting their turn there make a DC 27 Dexterity saving throw or fall Prone and take 22 (4d10) bludgeoning damage. Unattended structures take 40 damage at the start of each of Poseidon’s turns.
Mythic Trait — The Sea Rises. The first time Poseidon is reduced to 0 hit points, he instead regains 360 hit points. Water floods a 300-foot radius to a depth of 10 feet, storm winds fill the area, and he immediately uses Tidal Cataclysm.
Greater deity; alignment CN. Suggested divine encounter CR 33. Domains: Chaos, Earth, Strength, Water, Weather. Subdomains: Oceans, Storms, Ferocity, Resolve. Favoured weapon: trident.
Sea Sovereignty (Su). Poseidon has perfect freedom of movement in water and automatically controls non-divine currents, tides and ordinary storms within 10 miles. Aquatic creatures with fewer Hit Dice than his divine encounter CR begin encounters as friendly unless magically compelled otherwise.
Earth-Shaker (Su). Three times per day Poseidon may create an effect equivalent to earthquake as a swift action. Structures and ships take maximum damage from the effect.
Trident of the Deep (Su). Poseidon’s trident is treated as a major artifact in his hands. It may deal piercing, electricity or bludgeoning damage with each strike and can return instantly to his grasp from any distance on the same plane.
Greater deity; Divine Rank 17; alignment CN. Portfolio: sea, storms, earthquakes and horses. Domains: Chaos, Earth, Strength, Water. Favoured weapon: trident.
Appropriate salient divine abilities include Alter Reality, Divine Earth Mastery, Divine Water Mastery, Divine Storm and Irresistible Blows.
Divine Water Mastery. Poseidon dominates battle whenever he and his foes share the same body of water, can create devastating tidal effects and senses creatures through connected water.
Divine Earth Mastery. While in contact with the ground, Poseidon can feel movement through it and exercise supernatural control over earth and stone, reinforcing his ancient title as Earth-Shaker.
Lord of the Sea
The sea is Poseidon’s kingdom in the political as well as the elemental sense. Harbours, islands, straits, storms and shipwrecks all fall within his attention. He is not merely “a water god”: he is the divine power behind the fact that the sea can enrich a city one season and erase its fleet the next.
His trident is both weapon and sceptre. In myth it marks his authority over waves and earthquakes, and in play it makes him equally dangerous to ships, walls and armies.
Earth-Shaker and Horse-Father
Poseidon’s oldest powers reach beneath the sea. His epithets connect him with earthquakes, and his contests with other gods repeatedly show him striking the land itself when denied honour or territory.
He is also deeply associated with horses. In different traditions he fathers extraordinary horses, teaches or embodies horsemanship, and receives equine sacrifice and cult titles. Coastal cavalry, horse breeders and chariot houses can therefore honour the same god as sailors.
Worship in the Living World
Sailors pour offerings before departure, captains promise gifts for safe landfall, fishermen ask for calm waters, and coastal rulers maintain shrines where sea and city meet. Poseidon’s worship is practical because everyone who lives by the coast depends on a power that can never be treated as fully tame.
His priests read storms, tides, tremors and the behaviour of horses as signs. Their warnings are often politically inconvenient because a harbour-master may prefer profit to a divine omen telling every ship to remain tied up.
Poseidon and the Olympian Order
Poseidon is brother to Zeus and Hades. After the overthrow of Cronus, the brothers divide great portions of the cosmos between them: Zeus receives the sky, Poseidon the sea and Hades the underworld, while the earth and Olympus remain shared ground.
That division does not make Poseidon a subordinate provincial governor. He is a sovereign Olympian with enough power, lineage and cult to challenge other gods over cities, territory and honour.
What Is Poseidon Doing Now?
Across the Aegean, the sea has begun withdrawing from certain harbours at noon and returning at midnight without relation to the moon or weather. Ships grounded by the retreat find ancient roads, statues and walls exposed on the seabed.
Poseidon has forbidden his priests to claim the ruins. Something below the drowned settlements is waking, and the god would rather lose valuable coastline than allow mortals to break the seals before he understands what they contain.
Domain Spells and Divine Gifts
1st: create or destroy water, thunderwave · 2nd: gust of wind, shatter · 3rd: call lightning, water breathing · 4th: control water, freedom of movement · 5th: control winds, maelstrom · 6th: chain lightning, move earth · 7th: reverse gravity, whirlwind · 8th: control weather, earthquake · 9th: storm of vengeance, tsunami.
Divine Relic — The Sea-King’s Bridle
The Sea-King’s Bridle is an original game relic of dark bronze and sea-green leather. Any horse wearing it can breathe water, gains a swim speed equal to twice its walking speed and cannot be frightened by storms or supernatural waves.
Once per week the bearer may call a divine sea-horse from the surf. It remains until the next dawn and can carry riders across the surface of the sea as though it were firm ground.
Sacred Places and Cult Centres
Poseidon’s shrines favour capes, harbour mouths, islands, springs, earthquake faults and places where horses are bred beside the sea. His sanctuaries are often visible from ships before the city behind them comes into view.
Corinth, Cape Sounion and many island communities preserve powerful Poseidon traditions, while local cult titles emphasise particular aspects such as safe sailing, earthquakes, horses or civic protection.
Use Poseidon Tonight
- The Empty Harbour: the sea retreats and reveals a paved road descending toward a drowned city.
- The Horse from the Surf: a salt-white stallion carries a sealed bronze tablet around its neck.
- The Quaking Temple: a shrine shakes every sunset although the surrounding town feels nothing.
- The Broken Trident: one tine from an ancient divine weapon is found embedded in a fortress wall.
- The Storm That Waits: a hurricane remains perfectly still offshore until a particular ship leaves port.
Relationships
Zeus: brother, fellow victor over the Titans and political rival whenever Olympian authority overlaps with the sea.
Hades: brother and ruler of another great cosmic realm. Their domains meet wherever the dead are lost at sea or earthquakes open roads below.
Amphitrite: queen of the sea and Poseidon’s principal divine consort.
Athena: enduring rival in the famous contest for Athens and in the contrast between controlled civic strategy and Poseidon’s elemental sovereignty.
Demeter: sibling whose earth and fertility traditions intersect with some of Poseidon’s older horse and earth aspects.
Triton: divine son and herald of the deep.
Deep Link Dive
Hellenic Pantheon
Return to the complete Olympian, Titan and primordial directory.
Amphitrite
Meet the queen of the sea and Poseidon’s principal divine consort.
Triton
Follow Poseidon’s herald and the conch-call of the deep.
The Anemoi
Bring the directional winds into sea voyages, storms and divine weather.
Aeolus
Use the keeper of the winds when a voyage becomes a conflict between sea and sky.
Cleric
Build a priest, storm-prophet or maritime divine adventurer.
Salient Divine Abilities
Continue into divine-rank rules for epic play.
Sources and Licensing
Poseidon’s divine family, sea sovereignty, earthquake associations, horse traditions and mythic conflicts are drawn from ancient Greek literary and cult traditions, including Homer, Hesiod and later mythographers. The encounter statistics, relic, current events and adventure hooks above are original fantasy-roleplaying adaptations.
The 3.5e divine-rank material uses Open Game Content terminology from the Revised System Reference Document, including Divine Water Mastery, Divine Earth Mastery and Divine Storm. Edition names identify rules compatibility; the mythological traditions do not originate in those game systems.
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