A recurring summon and the avatar of water, Leviathan is a force to be feared in every one of his appearances as both an ally and an enemy. His personality and intelligence widely varies across all of his appearances, but all grow to respect The Sea King in all of his glory.

Tier: High 6-A|High 4-C |2-A

Classification: Eidolon, Ruler of the Seas|King of the Eidolons|Esper |Astral

Powers and Abilities: Superhuman physical characteristics, self-sustenance(Type 1), Acausality(Type 4), immorality(Types 2,3, and 7), regeneration(Low-Godly), shapeshifting, summoning, extrasensory perception, magic, subjective reality, non-physical interaction, law manipulation, limited Durability negation, forcefield negation, and intangibility, power modification, conceptual manipulation(Type 2), and space-time manipulation, BFR, time stop, and corruption(Type 2), water manipulation, ice manipulation, matter manipulation, weather manipulation(Can generate storms), electricity manipulation, and pain manipulation, summoning, gravity manipulation, healing, air manipulation, petrification(Via Demon Eye), resistant to the following: Subjective reality, magic, conceptual manipulation(Type 2), and space-time manipulation, law manipulation, chaos manipulation, reality warping, and memory manipulation, information analysis and Clairvoyance, mind manipulation, empathic manipulation, madness manipulation(Type 3), disease manipulation, poison manipulation and corrosion inducement, attack Reflection(Summons can bypass reflective barriers), darkness manipulation, perception manipulation, power nullification, berserk mode, existence erasure/void manipulation, mind manipulation(which includes Madness manipulation(Type 3),and perception manipulation), space-time manipulation, time-stop, and corruption(Type 2), petrification, biological manipulation, age manipulation, death manipulation and blood manipulation, soul manipulation/life force absorption, extreme cold and cosmic radiation, fire manipulation, ice manipulation, and matter manipulation, status effect inducement, morality manipulation and madness manipulation(Type 2), earth manipulation, light manipulation, water manipulation, sleep manipulation, paralysis inducement, absolute zero, transmutation, size manipulation, curse manipulation, sealing(Was sealed away by Noah, until he broke out after some time)

Attack Potency: Multi-Continent level(Has command of every major body of water on the planet)|Large Star level(As the King of Eidolons, he should be at least comparable to Lunar Ramuh, who can create a pocket dimension with a star, which is calculated to being this strong. The second strongest Eidolons, second only to Bahamut)|Multiverse level+(Gave Bartz's group a tough fight)

Speed: Massively Hypersonic(Comparable to Luneth and his group)|FTL(Is able to keep up with beings who far surpasses the speed of light)|Massively FTL+(Should be faster than Gilgamesh)

Lifting Strength: Class P(Could lift the contents of virtually any body of water on Earth)

Striking Strength: Multi-Continent level|Large Star level|Multiverse level

Durability: Multi-Continent level(Has command of every major body of water on the planet)|Large Star level|Multiverse level+

Stamina: High; not particularly tired after fighting the heroes as part of their tests to summon him and can soon be summoned immediately afterward

Range: Planetary(He has control over every body of water on Earth) Multiversal+ with magic(Magic as a whole is shown to affect omnipresent beings such as Exdeath when he's become one with the Void itself, which spans across the entire Final Fantasy Multiverse, can even banish foes into the Void with the Teleport ability)

Standard Equipment: None notable

Intelligence: Leviathan is one of the oldest and most powerful summons in every one of his appearances, his intelligence nevertheless varies between appearances. In some cases, he's a wise and ancient ruler, while he's a mindless or destructive beast in others. Regardless, what remains constant is the fact that he is ruthless in combat and has full mastery over his dominion of water and ice, drowning foes mercilessly should they face him unprepared. In Final Fantasy 14, he will parry projectiles with his tough skull, and reflect magic with his tail, showing a keen understanding and awareness on how to counter his foes.

Weakness: Due to specializing in the use of the oceans as a medium for his attacks, he is especially vulnerable to lightning-based abilities.

Notable Attacks and Techniques:

•Aqua Breath: Breaths out a gust of wind and sea water to blow away foes, dealing water and wind-elemental damage to all targets.

•Blizzaga: Conjures a blizzard to buffet foes with icy winds, dealing heavy ice-elemental damage.

•Cyclone: Leviathan generates a tornado that deals wind-elemental damage to all foes.

•Deluge/Tidal Waves/Tsunami: Leviathan raises all the sea into the air, bringing them crashing down as a catastrophic tidal wave to crush and drown his foes, dealing massive water-elemental damage.

•Demon Eye: Leviathan flashes an evil glare at his opponents, petrifying them and effectively killing them.

•Slowga: Slows down time around Leviathan's foes, heavily reducing their effective combat speed.

•Spring Water: Splashes allies with healing water, instantly restoring their vitality, closing wounds, and removing status effects like blindness, paralysis, and other impediments.

•Summon: Sahagin: His Final Fantasy 14 incarnation is able to summon his followers, the Sahagins, from the dephs to aid him in combat and disrupt his foes efforts.