First mentioned in the bible the leviathan is an ancient creature that many believe is the first mythical creature to be documented. It is an enormous almost otherwordly creature of unimaginable porportions it spends most of it's time sleeping for about 5 years at a time then it awakes and stays awake for up to a month where it starts looking for food. It has been known to devour whales almost whole and attacking ships to satisfy it's hunger. It doesn't move fast but it doesn't have to as it's immense size means one push from it's tail can propel it for miles easily catching up to any prey item it may be chasing.
It's size is unusual even for a mythical creature, but in the ocean evolution can go wild as their is no limit to size. What is clear about the leviathan is that it is related to an ancient reptile that once roamed the seas and managed to survive to the present day. It is a mosasaur, an enormous reptile that lived millions of years ago however the leviathan evolved into something so strange and unusual it defies reality. This holdover is rarely seen and very little is known about it because of it's environment the mirianas trench. The only known specimen dwells in the trench and dives by submersibles have yielded suprising facts. Samples of rock and skin taken from the creature have shown that it is in fact 1500 years old and is still an immature juvenile. Another fact about the creature is that it may in fact be the only known representative of it's species as no other specimens have been found.