Before the events of the game, Leviathan began to cause trouble in Liberte around the time of Glassworks Fair. Around this time Leviathan had sent his minions to make Captain Drake and his crew attack the city to steal all of the objects in Liberte's town hall. The Captain Drake and his crew stole Pione's vase with Lilibelle inside and the Rusty Compass. After the Rusty Compass was stolen, the Cetus was forced into an eternal slumber and city of Liberte was overrun by Leviathan's minions.
After being sent into the past, the party travels to Liberte a day before the events of the Glassworks Fair and help Pione by bringing Lilibelle for his vase. The next day, the party finds out that Captain Drake and his crew robbed the city of the artwork and kidnapped both Pione and Lilibelle. The party travels to the Pirate Hideout and discover that Captain Drake was being manipulated by Leviathan's minion. The party defeats the Sea Devil and free Pione and Lilibelle.
Captain Drake apologizes for his actions and gives the party the Rusty Compass. The party returns to Liberte and resurrect the Cetus. The party then takes the Cetus to the east and encounter Leviathan. The party defeats Leviathan and brings peace to Liberte. Later, Leviathan is revived within the Star Chamber, but it is defeated once more.
Leviathan is fought twice in the game, once on the world map outside of Liberte, and again in the Star Chamber.
Leviathan appears as a boss. In addition, Leviathan makes a cameo appearance when using the Envy ability.
Leviathan (Biblical Hebrew לִוְיָתָן or לווייתן Liwyāthān) is a violent sea creature that is referred to in the Hebrew Bible as well as the Talmud and some other ancient Jewish texts. During the golden age of seafaring, the term Leviathan became synonymous with any large sea creature, sometimes describing whales. Bible scholars interpreted Leviathan to be either a demonic sea creature and an enemy of God.
The Talmud and other ancient Jewish sources refer to Leviathan more specifically as a sea serpent, sometimes with multiple heads capable of breathing fire, that was made on the fifth day of Creation. It is said that during the end of days, God will make tents, or sukkah, out of the skin of Leviathan for the righteous to live in. Some have speculated that Leviathan was based on a real animal, the most popular theory being the Kronosaurus and the Nile crocodile.
Being mentioned in the Final Fantasy series as the King of the Seas, its incarnation also appears to derive from the legends of the Shinto god Ryūjin or Owatatsumi, said to be the dragon god that reigns over the tides and the seas. This is further reinforced by the parallels of the Leviathan faith of Wutai in Final Fantasy VII, as Shinto also sees the worship of water dragon kami in Japan.
In some cultures it is believed Leviathan lives at the bottom of Mariana Trench.