Leviathan is a classification given to extremely large creatures. Although the wording of the Reaper Leviathan's databank entry would seem to imply that the leviathan classification is exclusive to predatory life forms, this is not the case: any fauna species of a suitable size can be classified as a Leviathan.

Although the term "Leviathan" is used to refer to an aquatic creature in the real world, there is no confirmation on whether or not the Leviathan classification is restricted to aquatic fauna in the Subnautica universe, or is simply the term used for any species of a sufficient size.

Relation to Other Leviathans

Leviathan is not part of a taxonomic classification so does not imply any of the species classified as such are related.

Known Leviathans of the Arctic Mega Biome