Leviathans are docile sea creatures who dwell in the oceans of the Dragon Realms, only appearing in first two chapters of The Legend of Spyro series. They resemble giant sea turtles with three pairs of flippers.
During Spyro's first flight, a huge friendly Leviathan guided the young purple dragon towards Dante's Freezer as he traveled over the sea.
The Legend of Spyro: The Eternal Night
The same Leviathan appeared again, saving Spyro from possible drowning when he entered a dream in mid-flight after defeating Skabb. It brought him to the White Isle where the Chronicler resided. Once there, the Leviathan was thanked by Sparx as it swam off back to sea. The Leviathan was possibly sent by the Chronicer to take Spyro to the Isle after the Chronicler summons Spyro again.
Gallery
Two concepts of Leviathans
The 2D and in-game model of the Leviathan who has helped Spyro in his adventures