Leviathans are new creatures introduced in the spin-off comic of Sugar Bits; Braveheart Quest Robin Rescue. they are creatures who can transform from a normal looking object to a monsterous figure, just like to Nemo.
It is unknown if Nemo also is a Leviathan but it can be assumed he is one.
(† = confirmed death)
|Pirate Ship Leviathan||Active|
|Whale Submarine Leviathan||Active|