Four Horsemen of the Apocalypse

The Four Horsemen of the Apocalypse are four natures each having a separate conscience. They are astronomically powerful, and unable to die by any means. They take human form during the Apocalypse. They portray heralds of the Apocalypse, and are bearers of chaos. They are ultimately are triggered by Lucifer's release from the Cage. But they were very-much present even before Lucifer's release, just probably not physically. They are respectively known as: War, Famine, Pestilence, and Death. The Horsemen are neither angels nor demons, but rather a separate kind of being that cannot be destroyed.

Each possesses a special ring that allows them to channel and focus their powers (without which they are greatly hindered), and each, as tradition dictates from the Book of Revelation, travels in a car of their choice bearing the color of horse each is said to ride in the Bible (their choice of cars over horses being a sign that they have "gotten with the times"). The Horsemen are revealed to not truly be on either side, Heaven or Hell, but rather they are ultimately loyal to one another and their jobs for which they were created. After Lucifer rises from his cage in Hell, he takes command of the Horsemen (seemingly through the use of a binding spell to compel them to comply with his orders) and directs them in enacting his genocide against humanity. It is revealed however that at least some of the Horsemen resent Lucifer's use of them in his fight with God, ultimately revealing that he only has limited control over them. Their rings, unknown to all but a few select individuals, are the keys to Lucifer's Cage in Hell, and thus the Horsemen collectively hold the key to sending him back.

Powers and Abilities
They all may assume human form, teleport themselves anywhere (besides Famine, who is practically immobile, needing a wheelchair), overpower humans, and appear to be basically unstoppable.

They each have special powers which their own ring gives them, varying on the horseman, however Death doesn't need his, but wears it anyway.

The Horsemen
"I have three (siblings). And we're all so much fun together."

- The Horseman War

The Horsemen of the Apocalypse are extremely powerful beings in their own right, the Horsemen had up until this point been relatively idle; existing in a sort of multiple existence all over the world where their specific elements preside. War describes his life before the breaking of the Seals as being all over the place, more specifically existing where every major war in human history has taken place. Now that Lucifer is free, they have begun to up the stakes and spread their powers across the Earth to turn it into Hell.

In Death Takes a Holiday Alastair remarks the Horsemen are well aware of Lilith's plans and are "jonesing for the Apocalypse".

Unlike regular Demons or higher-tier Demons like the Seven Deadly Sins and white-eyed demons, the Horsemen are virtually indestructible. The only way to destroy them would be to annihilate all war, famine, pestilence and death in the world, though in "The Devil You Know" it is revealed that separation from their rings leaves them in a withered, near-catatonic state.

The Horsemen have a very slanted view of humanity and see themselves as just bringing out in humanity what is already there. Both War and Famine have said humans "only need a little push" in order to do horrible things, and both have surprisingly shown a level of disgust and contempt toward how easily corruptible humans are and what they can do. Pestilence prefers diseases to people, claiming that belief of disease being a bad thing is just because of sick people, and he can never understand why God has such love for humanity.

It is unknown if their human forms are constructions, illusions, or actual human vessels; Anna hinted that they may be using vessels when speaking to Castiel saying "The Horsemen can go back to their day jobs" once the Apocalypse has stopped. Another hint to what they actually are, would be that in the episode where the Introduce War (Season 5, Episode 2 "Good God, Y'all") War states that the person he is imitating is really dead burried in a ditch, which suggest, they do not require an actual human vessel, and that they can become whom ever the wish, more like a changeling, they can imitate, or construct an appearence of what ever they choose.

Each Horsemen also possesses a ring that allows them to channel and focus their power, and, while it doesn't kill them, separating them from their rings is the only known way to drive them off. In "Hammer of the Gods" Gabriel reveals the rings are actually the keys to Lucifer's Cage and if the brothers can collect all of them and trick Lucifer back into the cage, they can be used to reopen and close it.

In "Two Minutes to Midnight" it is shown that the Horsemen cannot be properly filmed, as when Dean and Sam are watching a camera for Pestilence they find him because his face and ring are hidden with a static-like distortion.

It also hinted that Lucifer may not have total control of the Horsemen as it is revealed in The Devil You Know that Dean and Sam are instructed to find Death and Pestilence's handlers in order to acquire their rings. Lucifer states in Abandon All Hope... that the Horsemen (Death in this case) are very demanding and it requires certain rituals and agreements to keep them happy and compliant. Their handlers are revealed in The Devil You Know to be more like personal attendants seeing to each Horseman's personal needs and overseeing some of their interests. Brady, for example, has been overseeing Pestilence's Croatoan Virus trials while the Horseman himself has been setting the stage for the virus's release.

The Horsemen also have a very deep loyalty to one another that supersedes any allegiance to Lucifer. For example, Pestilence wanted to kill the brothers in revenge for what they did to War and Famine. When a minion warned him they were under orders not to harm the brothers, Pestilence raised his voice to a Demonic level stating if the Devil wanted them so badly he could glue them back together after.

War
Appearing in "Good God, Y'all", War arrived in Rufus' town in the guise of a well known resident who he had previously killed a few nights before. In the Bible, he is said to ride a red horse but these days he "got with the times" and travels in a red sports car. Once in town, he destroyed the only exit from the town and then got to work on the people of the town by using his ring to generate hallucinations making the people believe that others around them had been possessed by demons. War hates acting directly because in his opinion the best way to cause chaos is to cause panic and let humans take care of the rest. Realizing that they could not kill War because the only way to do that would be to destroy all war in the world, the Winchesters instead cut off his ring finger, breaking the spell he had cast over the town and forcing him to depart. In The Devil You Know Brady reveals that the Winchesters have reduced him and Famine to near catatonic states. His ring is gold, does not have a stone, and appears to be a wedding ring.

Famine
Famine appears in My Bloody Valentine as a sickly old man. Improvements in farming and agriculture have severely weakened Famine, resulting in his sickly and weakened state. Because of this, Famine can barely infect anyone by himself, forcing Lucifer to send lower level-demons to care for him until his powers are fully regenerated. Despite his weakened state, he is still strong enough to resist an assault from a Demon-blood juiced Sam and explains all the Horsemen are immune to Sam's powers. Like his brother War, he too possesses a ring that allows him to focus and direct his powers. His ring is silver with a black stone.

Pestilence
Pestilence first appears at the end of Hammer of the Gods when he bought flu medicine from a small drug store, and spread some disgusting mucus over everything. He drives a sickly green/white car with a license plate that spells "sick and tired". He is accompanied by a swarm of flies and has the appearance of a man suffering a heavy cold though this appeared to be a ruse for after leaving the drug store he straightens up and laughs while throwing the medicine away. His ring is gold with a pale green stone.

Death
Death didn't make a physical appearance in Abandon All Hope..., but his presence was released from his prison in this episode. Lucifer released Death with his ritual. Although not seen on-screen, Death showed up and caused the dead to rise from the grave in Dead Men Don't Wear Plaid. He made his first visible appearance in Two Minutes to Midnight, where he was seen in Chicago. After getting out of his white car, he walks down the sidewalk, where a man on his cell phone rudely bumps into him and collapses dead soon thereafter. Crowley later helps Dean track Death to a pizzeria, where Death makes a deal with Dean to give him his ring in exchange for him do all in his power to put Lucifer back into his cell. His ring is silver with a white stone.

Death is the eldest of the Horsemen and is older than most creatures can understand; he explains to Dean that the entire galaxy is still "in its diapers" in comparison to him. In a conversation with Dean he claims to know God by stating that neither entity can remember their true ages anymore. Death's Sickle reacts in the same way as Dean's pendant reacts to God - glowing hot in his presence. Due to his age Death is very detatched from the rest of the world and does not really care that much for the Apocalypse and those involved, thinking them to be little more than bacteria. Dean, who is an important tool for the war, is highly insignificant to Death in the grand scheme of the universe, and he (like Pestilence) openly despises Lucifer, who has him under his control through the use of a binding spell. In a similar manner to Gabriel, Death compares Lucifer to a spoiled, bratty child throwing a tantrum and despises the fact he is using him as a weapon.

Family

 * Each other (Kindred)

Season 5

 * Good God, Y'all
 * My Bloody Valentine
 * Hammer of the Gods
 * Two Minutes to Midnight

Season 6

 * Appointment In Samarra

Season 7

 * Meet The New Boss