This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Leviathan (Jewish)
Leviathan is a sea serpent noted in theology and mythology. It is referenced in several books of the Hebrew Bible, including Psalms, the Book of Job, the Book of Isaiah, the Book of Amos. The Leviathan usually appears as a serpent or any type of sea creature she desires.
In truth, she is more a mix of many kinds of marine life into a singular all-powerful sea beast. Mortals are unable to fully comprehend its visage, so all they see is just its shade or a giant sea serpent. The Leviathan's features are both snake-like, kraken-resembling and with fish-like structure.