The Leviathan is a gigantic sea-monster of Biblical lore, and also one of the seven princes of Hell in demonology as well as the gatekeeper (taking the form of the "Hellmouth").
The Leviathan is one of the three beasts of the earth; it is specifically the beast of the ocean, with Behemoth being the beast of the land and Ziz being the beast of the air.
The Leviathan has become associated with any large and frightening sea creature in legend, such as the sea serpent or fictional whales (as mentioned in Moby Dick).
the Leviathan symbolises the wild and unpredictable side of the world's oceans, which were revered and feared in equal parts by the ancient world, the ocean was also the traditional prison for evil spirits, primordial gods and Lovecraftian Horrors in many religions and folklores from across the globe - the Leviathan can be seen as a merging of these primal fears and wonder, its dragon-like appearance and fierce nature is likely a symbolism for Satan himself and its continual struggle against God is seen as the primordial chaos of the past (the darkness prior to "light") fighting with the inevitable order of the future (the "World to Come").
- Most people believe that the Leviathan is either a whale, giant squid, shark, hippo, or a crocodile. Some creationists believe it is either a Plesiosaurus, Mosasaurus, prehistoric whale (such as Basilosaurus), Hadrosaurus, Megalodon, T. rex, or Spinosaurus. Some creationists believed the crocodile theory (which was mentioned in the Book of Job), but most likely say that it is a Sarchosuchus, a giant prehistoric crocodile. It is even notable that the fossil of Sarchosuchus has an unknown part on its jaw, which some believed that it breathes fire, since the Book of Job mentions that the Leviathan can breathe fire.