Who Is Leviathan in Supernatural

Is Castiel a Leviathan?

Leviathan Castiel is the main antagonist of the Meet the New Boss Supernatural episode, he was the first Leviathan the Winchesters faced him, as he was psychopath who liked to inflict pain on others, yet he was never seen again. He is portrayed by Misha Collins.

Did Sam and Dean kill the Leviathan?

However, these plans are foiled when Dean and Sam Winchester break into SucroCorp, and Dean stabs Dick Roman with their weapon, killing the Leviathan leader, though Dean and Castiel are transported to Purgatory in the process.