The Leviathan is a monstrous creature with a mix of crocodilian and cetacean characteristics that is mentioned several times in the Hebrew Bible. It basically states that the Leviathan is literally the biggest bad-ass on God’s green earth. The Leviathan’s existence is essentially a statement of the power of God. I think that statement would be “Look upon my works ye mighty and piss yourselves.”
According to some later Jewish literature the Leviathan is a widower; After God made the first two such monstrous sea-dragons he decided that letting these critters procreate wouldn’t be such a hot idea, so he killed the female. Yep, that’s right; the Leviathan isn’t just the biggest, meanest ass-kicker on earth; it’s the biggest, meanest ass-kicker on earth and it’s horny (and probably bitter too). Actually, the Tarasque is said to be the result of an apparently desperate pairing between the Leviathan and the Onachus, a creature said to incinerate almost anything it touches (I did say desperate).
Like the Jormungander, the Leviathan is prophesized to meet its final fate at the end of the world. In thise case, at the end times it will be slain by God and used to provide the believers with meat for the most epic buffet in history. Anyone who’s ever seen seen Southern Baptists hitting a Chinese buffet after Sunday services will understand the necessity for such copious amounts of foodstuff.