Bone of Righteous Mortal Washed in the Three Bloods of Fallen

Bone Of the Righteous Mortal washed in the three Bloods of Fallen is the Only thing that can kill a Leviathan

In the Episode Reading is Fundamental, Sam and Dean meet Prophet Kevin tran who translates them the word of God that says that a Bone of a righteous Mortal dipped in the three bloods of Fallen can kill a Leviathan. At the end of the episode Castiel gives them the Fallen angel blood

Further in There Will be Blood Dean reads on the translation of The Word that reveals if they Cut the head-Dick Roman then the body-rest of Leviathans will flounder.They then Meet with the Alpha Vampire who gives them his blood after learning that the Leviathans are planning to wipe out the other Supernatural Races.

In the Season Finale Dick tries to convince Crowley to give the Winchesters a fake vial of blood but Corwley gives them the true one.Meanwhile the Winchester's use the bone of a nun Sister Mary Constant to forge a weapon and attack Dick Roman at Sucrocorp accompanied by The Impala,Meg and Castiel.

Castiel and Dean confront Dick, Dean stabs him with a fake bone. Castiel then catches him offguard and Dean stabs Dick in the neck with the Bone.

Dick after being stabbed starts releasing a strange aura all around the room as Cass and Dean stand confused with Dick smiling.



After some time he explodes spreading black Leviathan goo all over the place and his soul goes back to Purgatory but he somehow takes Dean and Castiel with him.