Leviathans are most prominently found in the Sea of Leviathans, however there have been sightings of them in the east and south of Gaeia. They usually inhabit cold and deep waters in the north.

They can be seen swimming in peculiar patterns, creating arches with its body in order to swim. They find themselves picking on ships and fish alike, terrorising anything in its path, but this is justified due to their large bellies they need to fill. Leviathans usually travel alone, and don’t really stick around in one area. Eggs are usually abandoned after a while of the mother sticking around, so when babies hatch they find themselves alone for the most part. When hunting, leviathans will use hydromancy to boost themselves towards their prey momentarily to catch them before they swim away.

Their bone structure is comparable to those of a serpent, only much bigger.  A leviathan's teeth are very sharp, being able to crush bones with ease, and cut through flesh like butter. 

Length: 6 - 7 miles

Weight: 40 - 60 tons

Bite Power: 33,000 - 35,000 psi

Swim Speed: 25 - 30 knots (30 - 40 when momentarily accelerated using hydromancy)

Average Hydromancy Acceleration Time: 10 seconds

The leviathan is an incredibly intelligent species when it comes to fighting their prey, however fighting seems to be the only thing they are good at. Leviathans will usually crush large objects on the sea's surface with their weight if they can't get their teeth around it, which is one example of their great problem solving skills. If they receive heavy damage to the skull, they will go completely haywire and flail about in rage, practically losing all intelligence previously shown.

River Leviathans, In short, the River Leviathan is a more gator-centred Leviathan, their skin ranging from a deep green to a muddy brown depending on the place they find themselves in. RL’s are specialised ambush predators where their jaws are larger than a normal Leviathan to fit more muscle for a stronger bite. Their weakness could be like normal gators, most of their muscles are bringing the jaw down, not lifting it up, which means you could easily hold their mouth shut. Note that the river leviathan is incapable of using hydromancy in any way. 

The Deep-sea Leviathan tends to be a lot more aggressive than a regular leviathan, and will pick a lot more fights especially with larger species, sometimes other leviathans, but both leviathans usually come out with severe injuries and not much else. They are huge and hunt with bursts of speed, going on a drawn out hunt will cause them to lose interest in the target and go dormant. They have a heavier use of their Electroreception and sense of smell since there is no light that deep down where they reside.

Dwarf Leviathans, like pygmy elephants, have grown tiny and small due to being isolated in isolated water systems, where they hunt the smaller prey that live in these ecosystems, and have gone downwards in size due to the smaller amount of available prey. They can grow up to 20 - 30 metres in length, around half the size of a normal leviathan. They are quite fearful of larger species, and are a lot more vulnerable to them, usually fleeing when encountering one. However, they are subject to a lot less of these creatures due to their smaller living environments.