Changes

|powers and abilities= <br>* Regeneration* [[Shapeshifting]]* Super strength, regeneration, possession, shapeshifting.|vulnerabilities= <br>* Blood of the Fallen* [[Borax]], beheading and powerful [[spells]] can temporary incapacitate them. Blood of the fallen, being eaten by another Leviathan and "bibbing" can kill them.* Decapitation

When [[Castiel]] opened the door to Purgatory and took in the power of the souls stored there to increase his own angelic power, he also took in the Leviathans. With the help of [[Sam]], [[Dean]] and [[Bobby]], Castiel was able to expel the souls back to Purgatory, but some of the Leviathans "held on." Castiel's vessel was taken over by the Leviathans, however it quickly began to deteriorate forcing the Leviathans to guide Castiel's vessel into a nearby water catchment just before the vessel disappeared in imploded, creating a whirlpool, and releasing them into the water supply.

The number of Leviathans that escaped from Purgatory is unknown. The Leviathans operated within , though Dean suspected that possibly over a rigid hierarchy lead by [[Dick Roman]]hundred were in Castiel's vessel at the same time.<ref name="seven02">[[7.02 Hello, Cruel World]]</ref> The Leviathans operated within a rigid hierarchy lead by [[Dick Roman]]. Their ''modus operandi'' was to take on the forms of humans who have valuable skills, or were in positions that may be useful, particularly positions of power including the military and corporations. Dick Roman stated their golden rule was, "There's no such thing as monsters." Their plan, as revealed by [[Bobby Singer]], was to turn humanity into the perfect never-ending food-source. To accomplish this, they were building slaughterhouses for humanity in various locations and were putting an additive into the food that made humans pliable and easily controlled. The additive would also kill all monsters that feed on humans such as [[vampire]]s, [[werewolves]] and [[ghouls]]. The Leviathans would also develop a version that they put into coffee creamer that would breed out unwanted traits (naturally lean people, short people, hemophiliacs, and those with a high IQ) and kill people who have such traits. The Leviathan also planned to build centers to cure diseases like cancer, so that their food supply would be disease free.

After the death of Dick Roman, any of the remaining Leviathans still on Earth cease to be a threat. By one year later, their influence seemed to be completely gone from the world as people were shown to be back to normal and Sam and Dean were able to eat normal food without apparent worry about the food additive.

The Leviathans have sharp teeth within an expanding jaw, and possess a bifurcated tongue. Because of this trait, Sam and Dean often referred to them as "big mouths." As shapeshifters, Leviathans can mimic a particular human being following simple contact with one, or if they obtain any type of DNA from a person, from skin cells to strands of hair. They are able to copy a human so perfectly they have access to that person's thoughts and feelings, and even insanity.<ref name="seven06">[[7.06 Slash Fiction]]</ref> All the Leviathans that escaped [[Purgatory]] absorbed everything that [[Castiel]] knew, as he was their original vessel. When wounded they "bleed" black goo.

They prefer to feed on human internal organs – sometimes with cheese, however [[Leviathan!Sam]] once related to [[Leviathan!Dean]] that had a brother with many issues, and that he ate him in the end – so they are not averse to cannibalism. This is later shown when [[Dick Roman]] eats [[Victor]] and [[George]] and revealing his plans to eat [[Joyce Bicklebee]], with George telling the Winchesters that a Leviathan eating another is one of the only ways to kill them.

A severe punishment among the Leviathans is known as "Bibbing." First mentioned by Dick Roman when he told [[Valente]]: "Next time, call me with a win. For your sake. Please don't make me bib you."<ref name="seven06">[[7.06 Slash Fiction]]</ref> When Dick decides that [[Dr. Gaines]]' experiments are drawing too much media attention, he decides to bib him. This involves literally placing a bib on him, and then Dr. Gaines eats himself until nothing is left – except a goo stained bib. This is one of the only known methods of eradicating a single Leviathan for good.

* Can kill angels – Leviathans predate angels, which allows them to overpower them easily. They are immune to an angel's power and can kill them angels by forcing their fists into the angel's stomachchest, causing black ooze to purge the angel to then ooze black goo and diefrom the inside.* Enhanced endurance and regeneration – Leviathans are extremely resilient, surviving multiple shotgun blasts with silver buckshot or taking a shot, including one to the head at point blank range. One also survived and reassembled [[Edgar]] was able to reassemble itself after being crushed by a falling car. They can even re-attach their heads if decapitated.<ref name="seven02">[[7.02 Hello, Cruel World]]</ref><ref name="seven06">[[7.06 Slash Fiction]]</ref>* Enhanced senses – The Leviathan Edgar was able to smell Sam and Dean Winchester within the Alpha Vampire's mansion.

* Intelligence High intelligence – Many of the Leviathans are known to possess vast knowledge on almost all the world's secrets, including the ability to cure cancer among other diseases. Their intelligence also allows them integrated seamlessly into society, making hunting them extremely difficult.* Immunity – They are immune to an angel's power and most weapons devised by mankind.* [[Possession ]] – Leviathans can possess any human they come into contact with in through their fluid form, be it through physical contact or a human drinking it. This person becomes their physical embodiment of sorts. These shells bleed black ectoplasmic looking blood when injured and can reshape their jaws to display long sharp teeth and a two-pronged tongue.* [[Shapeshifting ]] – Once a [[vessel]] is taken they can reshape it into any human form they touch. They require only a fragment of DNA to transform into a person; even lost hair will do. The creature possessing a little girl takes the form of a doctor by touching his arm. They can also absorb the memories of anyone whose form they take, much like a [[shapeshifter]], but without requiring the person to remain alive. This ability extends to absorbing a victim's mental state as well, as evidenced when the [[Leviathan!Sam]] revealed he was having visions of Lucifer torturing him. It is revealed that there are certain humans like [[Charlie Bradbury]], Bruce Springsteen, and Eli Manning who possess a certain "spark" that means they cannot be emulated as perfectly.* Super strength – They are shown to possess greatly enhanced strength; at their first meeting, they are able to hurl Dean and Bobby across a room with little effort. Leviathans predate angels, demons, and all other monsters, which allows them to overpower them easily.

* [[Borax]] – Leviathans are highly susceptible to materials that contain the chemical compound borax (sodium borate) such as household cleaning products. Contact with their skin results in an instant burning effect that can reduce them to charcoal-like husks if they are exposed to too muchfollowing prolonged exposure. A Leviathan will eventually heal from the effects, though the length of time depends on the severity of exposure. [[Dick Roman]] was shown to be less susceptible to the chemical, healing nearly instantly after a borax bomb blew up in his face.<ref name="seven09">[[7.09 How to Win Friends and Influence Monsters]]</ref>* Beheading – Removing a Leviathan's head disables them temporarily. But unless the head is kept far away from the body it will re-attach itself. The combination of burning them with borax and then beheading them and separating the head and the body appears to be the only way to put them down indefinitelyeasiest method of indefinite dispatchment, assuming the head has no way of finding its way back to the bodyor if any surviving Leviathans can locate the head as well as the rest of the remains.Head trauma can also disorient Leviathans for a few seconds, as shown when Bobby shoots Susan with one of Dick's revolvers and whacks a security guard with a nearby crowbar.<ref name="seven09">[[7.09 How to Win Friends and Influence Monsters]]</ref>* Blood of the Fallen – The [[Tablets|Leviathan tablet]] states that a Leviathan can only be killed by a bone of a righteous mortal soaked in the bloods of the fallen. The bone must come from someone as light and good as the Leviathan are hungry and dark. There are three fallen whose blood is required; the first of these is a [[fallen angel]] (Castiel's blood qualified). The other two fallen are the ruler of fallen humanity (meaning [[Crowley]], the King of Hell) and a father of fallen beasts (an [[Alpha]]). Once this weapon is assembled, the Leviathan only needs to be given a fatal blow to be killed, but it can result in those nearby being pulled to [[Purgatory]] with the Leviathan.* [[Clairsentience]] – After the Leviathans took control of Castiel's vessel, he gained the unique ability to tell them apart no matter what form they take. This proves to be key to identifying the real Dick Roman after he had a group of security guards to take his form and planted them throughout SucroCorp headquarters to disorient the Winchesters.<ref name="seven23">[[7.23 Survival of the Fittest]]</ref> In general, it also appears to be one of very few ways to confirm if someone is a Leviathan.

* [[Edgar]] (neutralized) – A Leviathan whose vessel worked in demolitions. Edgar was neutralized after a confrontation with the [[Alpha Vampire]], allowed [[Sam Winchester]] to decapitate him.

* [[Chet]] (neutralized) – Leviathan who works for a credit card company assigned to track down Sam and Dean Winchester. Chet was neutralized when Bobby Singer discovered the Leviathan's weakness to [[borax]], he . He was decapitated and his head given to [[Sheriff Jody Mills]] to toss over a bridge.

* [[George]] (neutralized) – Joyce's assistant.

* Multiple SucroCorp personnel (neutralized) – Assaulted and decapitated by Crowley's demons* [[Purgatory]] Leviatahans Leviathans (neutralized) – Four seen decapitated during Dean's time in Purgatory, who were decapitated.

* Fred Savage<ref>[[7.14 Plucky Pennywhistle's Magical Menagerie]]</ref>

After having revealed themselves to [[Dean]] and [[Bobby]], the Leviathans quickly realize they cannot remain inside [[Castiel]]'s [[vessel]] as it begins to rapidly burn up and are forced to leave for the time being; they promise to return and finish what they started. [[Leviathan!Castiel]] staggers out into the open and submerge themselves in a nearby municipal water source, abandoning the vessel, leaving only Castiel's bloody trenchcoat trench coat behind.

[[Victor Rogers]] mentions the past Leviathan situation as a "fiasco" and a "wake up call" saying that it showed him how vulnerable the current generation of hunters really are compared to the monsters they risk their lives fighting and killing and dying over."