In Granado Espada, Bracelet of Leviathan is a Lv.100 ice bracelet (AR30) for the elementalist. This entry is the first of its category, dealing with fictitious in-game names and real world analogs.
In that day the LORD with His severe sword, great and strong, Will punish Leviathan the fleeing serpent, Leviathan that twisted serpent; And He will slay the reptile that is in the sea.
On the 5th day of creation, God created the fishes out of fire and water. Leviathan ruled over them as the king of fishes in Jewish legends. The female Leviathan was killed by God to stop the inevitable destruction of the world should the Leviathans produce offspring.
Its eyes and fins are radiant, and the gigantic fish served as God's plaything. Its smell however is foul. The Leviathan lives in the Mediterranean Sea, and the waters of the Jordan River flows into its mouth.
According to the Talmud, the Leviathan is destined to serve as a delicacy for the pious in the world to come. When that time comes, the warring angels will be defeated and will flee from the Leviathan. God will then command Behemoth and Leviathan to duel each other (... possibly at the PVP officer in Auch). The two monsters will slay each other. Leviathan's skin will then be used as a canopy to shelter Jerusalem.
William Blake also mentioned Leviathan in his famous work, The Marriage of Heaven and Hell.
Sources: Jewish Heritage Online Magazine ☼ Wikipedia