Levias

Levias is a wise, whale-like Sky Spirit that lives in Thunderhead in Skyward Sword. Since ancient times, Levias watched over the skies and is knowledgeable in many things. Levias was corrupted by evil forces and is plagued with parasitic eye-like appendages.

Etymology
Levias's name is derived from Leviathan, a mythological monster from Biblical text. Fittingly, in modern Hebrew, "Leviathan" means "whale".