Leviathan

Leviathan, also dubbed Titanus Leviathan, is a giant aquatic daikaiju created by Legendary Pictures to appear in the MonsterVerse. Leviathan appears in Legendary's 2019 film, Godzilla: King of the Monsters, as a name appearing on a monitor, and it is briefly mentioned in Godzilla: King of the Monsters - The Official Movie Novelization.

Godzilla: King of the Monsters
Leviathan was found in Loch Ness, Scotland, by Monarch, and Outpost 49 was built around it. When Ghidorah calls all the Titans, Leviathan breaks free and begins to hunt with its new pack. When the ORCA calls all Titans to Boston, Leviathan does not arrive in time for the battle and does not see Godzilla become the new alpha of all Titans (except Kong).