It is described as the deepest, most heavily protected part of Hell. It currently holds the Archangel Michael, as well as Michael's substitute vessel Adam Milligan. Sam Winchester also spent some time in the Cage, but was "rescued" by Castiel. He was unable to raise Sam with his soul, so it spent well over a year (more than 120 years in Hell time) in the Cage being tortured by Lucifer and Michael until Death finally retrieved it.
According to Lucifer, the cage was damaged by the release of The Darkness, allowing him to send visions to Sam to manipulate him into returning. After a brief fight with Dean, Sam and Castiel, Lucifer possessed Castiel with consent, allowing him to escape the Cage.
The cage compared to the main frame of Hell, according to Castiel, is heavily guarded, more so than when Dean was in Hell. During his time in the Cage, Sam is seen surrounded by flames (conforming to Death's description of it as a "fiery pit" - or Death may just have been referring to Hell in general). Ironically, the Cage seems to have multiple entrances and can be opened with several various ways. Unlike angels, fairies including the Leprechaun, may be able to enter the Cage undetected, as they have a way of getting through "back doors" of prisons, though Castiel finally admitted that he was the one who raised Sam. Despite the complexity of the Cage, Death travels through the Cage unaided, successfully retrieves Sam's soul, returns to Earth, and places it inside Sam.
The fact that Lucifer's Cage can be opened from almost any point on Earth, (as Dean opened it in a house in Detroit and later on Sam opened it at Stull Cemetery) implies that it has an existence in another dimension or a separate plane of existence, evidenced by Dean's description of time passing differently in Hell.
In Season 11, the Cage is seen from an outside perspective for the first time; it is shown to be a rectangular cage of an archaic design covered with Enochian sigils and runes suspended on a multitude of chains in the midst of a dark void filled with fog and cut through by bolts of lightning. This echoes the original design of Hell seen in Season 3 when Dean was sent there by Lilith.
Lucifer was once God's most beloved child. However, when God created Humanity and ordered His angels to bow down before them, Lucifer refused. Lucifer argued that Humanity was grievously flawed and used this to justify his actions, though in reality he was merely jealous that Humanity had replaced him in the foremost of God's affections. After God cast him out of Heaven, Lucifer decided to mock God by twisting a human soul, Lilith, into the first demon, corrupting the Garden of Eden, and giving Cain a demonic mark. For these unforgivable offence's God created the Cage - a prison cell within the deepest part of Hell. He then ordered his strongest, eldest angel and Lucifer's older brother, the Archangel Michael, to cast Lucifer into the Cage for all eternity. Lucifer pleaded with Michael to take his side instead, but Michael obeyed his Father's command and cast his brother into the Cage.
The door of the Cage, originally located where Ilchester, Maryland would be founded millennia later, was then locked with a series of Seals, known as the 66 Seals, designed to prevent Lucifer from escaping Hell unchecked. Though there were well over 600 Seals, only 66 of these needed to be broken for the cage to open and Lucifer to be released, though the first and last Seals would be specific. The first Seal, which had to precede any others for them to be effective, would be broken when a righteous man would spill blood in Hell, meaning that as he would break, so would it break. Meanwhile, the first demon, Lilith, would be the last Seal, and as she would be broken, so would it. God also secretly created a set of master keys that - when combined - could open and close the Cage at their owner's will. These keys were the four personal rings of the Four Horsemen of the Apocalypse.
Though none of the demons knew the location of Lucifer's prison, a church known as St. Mary's Convent would come to be built right over the very spot which the door of the Cage was originally located. Eventually, Azazel would find it, and from here, would speak to Lucifer for the first time in many years.
Season 4Season 4 finale, "Lucifer Rising". In the opening of the episode, which takes viewers back to the year 1972, the Yellow-Eyed Demon, Azazel, is revealed to have escaped Hell and to have discovered the truth of St. Mary's Convent, that it's the location of Lucifer's Cage, after having wandered for years looking for it. He travels to Ilchester, Maryland and takes possession of the head priest, disemboweling eight nuns shortly thereafter during a mass in the convent's main chapel. Draping the head nun's bloody corpse over the altar, Azazel beseeches Lucifer to "whisper through the door" of the cage. Azazel successfully makes contact with the imprisoned Devil, who commends Azazel's faith in him and his ability to locate the Cage's entrance. Lucifer reveals to Azazel that Lilith, who is at this time locked away in Hell, is needed to break the Seals and set him free. It is here that the plan involving the Special Children is conceived by Lucifer and Azazel, with the aim being that the special child would be the one to ultimately kill Lilith to ensure Lucifer's release and then to serve as his vessel to lead the army of Hell against God in the Apocalypse that would soon follow.
Several decades later in 2007, Azazel orchestrated the release of Lilith through the Devil's Gate in Wyoming just moments before his own death, though this ensured that his plan to release Lucifer was now set into motion. In the year of 2009, Dean Winchester has long since broken the first Seal during his time in Hell before his rescue and 64 of the other Seals have by this time been broken, leaving the final Seal the only thing standing in the way of Lucifer's release. Sam Winchester, unaware of Lilith's status as the final Seal on Lucifer's Cage, eventually follows the first Demon to the now-abandoned St. Mary's Convent in Ilchester, Maryland. By this time, Ruby has gotten Sam addicted to Demon Blood, which enhances his demonic powers and secretly prepares his body to hold the Devil's essence, and accompanies him to the chapel to confront Lilith. Meanwhile, Dean learns during his sequestering by the Angels that Lilith is the final Seal and that her death will ensure Lucifer's release. Castiel, troubled by his conscience about what will happen to Humanity once The Apocalypse begins, disobeys his orders and accompanies Dean to the home of the Prophet Chuck Shurley to learn where Sam has gone. Though they learn the truth about St. Mary's Convent from Chuck, the Archangel Raphael begins to descend upon the house and Castiel remains behind to hold him off while teleporting Dean to St. Mary's to stop Sam from killing Lilith.
Dean arrives just as Sam pins Lilith to the altar in the convent's chapel, where years before Azazel had committed the bloody massacre of the nuns. Ruby turns and smiles at him before raising her arms and telekinetically locking the chapel's doors, locking Dean out. Though Dean attempts to break into the chapel and screams for Sam to stop what he is doing, Lilith's taunts are enough to push Sam over the edge and finally use his full power to kill her, unknowingly breaking the final Seal on Lucifer's Cage beneath their feet. As Lilith's blood pours from her mouth and forms a spiral circular sigil in the center of the chapel, Ruby reveals that the first Demon, Lilith, was the last Seal, and that she and Lilith were working together all along to release Lucifer from his cage. She tries to convince Sam that Lucifer will repay him in ways he cannot imagine, moments before Dean finally breaks through the chapel's doors as Sam holds Ruby, disgusted by her treachery. Dean then kills Ruby with her own knife. Sam apologizes to Dean, but the two brothers turn and watch in horror as the circle of blood begins to turn, revealing the mouth of Lucifer's Cage opening, allowing the Devil to rise out of Hell and ascend to the Earth.
Moments before the Devil fully escapes his prison, God teleports the Winchester brothers out of the chapel and onto a plane passing over Ilchester at that moment, from which they witness Lucifer's angelic essence shoot up into the sky from the spot where St. Mary's Convent had stood before being blown apart by the Devil's escape from his cage, heralding the beginning of The Apocalypse.
The archangel Gabriel reveals posthumously, before being killed by Lucifer, that Lucifer's Cage, which was opened when the 66 Seals were broken, is still down in Hell and can still be used to contain Lucifer if it can be reopened and Lucifer tricked back into it somehow. He reveals, believing that Lucifer is not aware of it, that the original keys to the cage are the rings worn by the Four Horsemen of the Apocalypse. He suggests that if the Winchesters can gain all four, they will have the cage as an answer to stopping the Apocalypse from devastating the Earth and destroying Humanity. However, the Archangel reveals that this will not be easy as they must first get the cage door back open and then devise some way of tricking his brother back into it before shutting it again.War, Famine, Pestilence and Death, the Four Horsemen of the Apocalypse holding the keys to Lucifer's Cage. After successfully acquiring the rings of War, Famine, and Pestilence by force and learning of the latter's plot involving the Croatoan Virus, Sam goes with Bobby to stop the virus' outbreak while Dean goes with Crowley to Chicago, Illinois to acquire Death's ring. In Chicago, Dean has a civil conversation with Death, who openly despises Lucifer and the fact that the Archangel is using him as a weapon through the use of a binding spell just to throw a tantrum and display his displeasure to his Father, God.
Death, who has no real interest in the Apocalypse and sees both it and its players as insignificant in the grand scheme of the Universe, agrees to willingly hand over his ring to Dean in exchange for Dean's promise that he will do absolutely everything necessary to put the Devil back in his cage and thus free him of Lucifer's service, even if this means Sam losing his life to do so. The Horseman warns Dean to hold true to his word as he can't "cheat Death" and gives Dean the instructions on how to work the rings, which combine to form a key-like device that controls the opening and closing of Lucifer's Cage.Season 5 finale, where Dean, out of options, decides to go along with Sam's plan that, as Lucifer's true vessel, he will consent to possession by Lucifer and fight him for control long enough to throw himself into Lucifer's Cage, taking the Devil with him. The group tracks Lucifer to Detroit, Michigan, the very place Lucifer had told Dean in one possible future that they would meet and Lucifer would acquire Sam as his vessel. Sam drinks an enormous amount of demon blood in order to prime himself to contain Lucifer's essence and says his goodbyes to everyone before going with Dean to confront the Devil. His current vessel heavily deteriorated, Lucifer hears out Sam's proposition to give his consent for possession, Sam proving his seriousness by effortlessly killing Lucifer's demon bodyguards with his demonic powers. Lucifer reveals however that he knows about their plan to trick him back into his Cage and that the rings control it. Despite this, Lucifer likes the idea of an internal battle and gives Sam a proposition: if Sam can ultimately overpower Lucifer for supremacy, he may jump into the hole leading to Lucifer's Cage and take the Archangel with him; but if Lucifer is able to overpower Sam, then he wins all. Sam consents, and the Devil quickly abandons his vessel to become one with Sam, knocking both of them out momentarily. This gives Dean the chance to open the cage using the Horsemen's rings. Sam recovers and walks toward the portal before turning and smiling, revealing that Lucifer has overpowered Sam and is now in control of his body. He closes the cage, takes the rings, and vanishes.
Lucifer travels to Stull Cemetery in Lawrence, Kansas to meet his brother Michael for their final showdown the following day. However, before the two can act, Dean arrives in the Impala and demands to speak to Sam. Though Michael (using Adam Milligan as his vessel) protests his presence, Castiel hurls a holy oil Molotov cocktail at him, causing him to vanish for several minutes and giving Dean time to try to reach Sam. Lucifer, outraged at Castiel's audacity, snaps his fingers and obliterates Castiel before telekinetically snapping Bobby Singer's neck after he attempted to shoot the Devil, who was brutally beating Dean on the hood of the Impala.
The Archangel tells Dean between blows that he will break every one of Dean's bones and make Sam feel it. Dean does not resist however and merely tells Sam that he will not leave him. As Lucifer goes to land another blow, he glances into the back seat of the Impala, where he glimpses an old army figure stuck in the ashtray that was put there by Sam in his childhood. Suddenly the Archangel is overwhelmed by all of Sam's happy memories of his life with Dean. Sam's love for his brother, stimulated by this rush of memories, is sufficient to break Lucifer's grip on Sam's body, allowing Sam to take control of his body at last. Sam tells Dean that everything will be all right and that he now has Lucifer. He tosses the Horsemen's rings to the ground and recites the incantation that activates them, opening Lucifer's Cage in the heart of the cemetery. Just as he is about to throw himself into the pit, Michael returns and demands a fight to kill Lucifer, stating that it is his destiny to do so. Sam ignores this however and outstretches his arms, beginning to lean toward the pit. Though Michael tries to stop him, he only ends up being pulled down into the pit alongside his brother as the cage shuts once again in a thunderous flash of white light, leaving behind only the red-hot rings of the Horsemen. After being healed by a restored Castiel, Dean goes to see Lisa Braeden and sits down to dinner with she and her son while outside, a streetlight flickers. There standing beneath it is Sam, freed from Lucifer's Cage by Castiel but without his soul.
Sam starts remembering a portion of events that happened when he lacked a soul. After Sam and Dean resolve the murders, Sam falls onto the floor, shaking uncontrollably, where he recalls some of the torture he endured in Hell by Lucifer, and is seen covered and surrounded in flames. He screams as the flames burn his face.
A portion of Sam's time in the Cage is briefly alluded to, though not really seen.
The hallucination of Lucifer compares the locked ward to the Cage.
Shortly after Sam prays to God, he receives a vision of himself being tortured in the Cage.
Sam mentions to Dean that he is receiving visions of Lucifer's Cage again and wonders if it has something to do with stopping the Darkness. Dean tells Sam that they've been down that road and nothing good to be found there.
Sam gets a vision of himself in the Cage with Lucifer and has a feeling of peace when Lucifer touches him. More sure than ever that God wants him to go to Lucifer, Sam and Dean call upon Crowley for a safe way to speak to Lucifer in the Cage where his powers are neutralized and Sam will be safe. Crowley captures his mother Rowena and with her help and the Book of the Damned, they are able to find a way to summon Lucifer into a smaller cage in Limbo where he will be warded and surrounded by holy fire. Lucifer appears in the cage, manifesting in the form of Nick and they explain they need his help against the Darkness. Lucifer tells Sam he needs a vessel to help and wants Sam to be it. Sam ultimately refuses, but the warding suddenly fails and Lucifer teleports Sam into the cage with him. Lucifer finally explains that the visions were from him the whole time: the release of the Darkness damaged the Cage enough that Lucifer was able to reach out and implant the visions into Sam's mind. Sam is left trapped in the cage with Lucifer once more, terrified.
Lucifer takes Sam through memory lane to convince him that he needs Lucifer to defeat The Darkness. Sam is not convinced, believing Lucifer to be playing tricks again. According to Lucifer, Michael, who is still in his Cage, has been driven insane by his imprisonment. When Sam still refuses to give Lucifer consent, the archangel begins attacking him.
Dean and Castiel arrive in Limbo and join the fight. Before Rowena can send Lucifer back to his Cage, Castiel gives the archangel consent to possession over his vessel, allowing Lucifer to walk the Earth once again.
The Winchesters, Crowley and Rowena team up together in an attempt to expel Lucifer from Castiel and send him back to the Cage. Their efforts are ultimately unsuccessful and Lucifer is instead captured by the Darkness.
While discussing their options for battling the Darkness, God tells them that Lucifer is the only archangel that can help them as Raphael and Gabriel are dead and Michael, trapped in the Cage and insane, is in no shape to help them fight.
- Sera Gamble described the Cage as being "at the bottom of the lowest depths of the ninth circle of the worst bit of Hell." 
- Rowena claims to be the only one who can open the Cage.
- In We Happy Few, God doesn't release Michael from the Cage due to him being in no shape for a fight. He also shows no inclination to release Michael at all even after reconciling with Lucifer meaning there is no need for Michael to want to kill him if he is freed.
- ↑ Swan Song
- ↑ 2.0 2.1 Appointment In Samarra
- ↑ The Man Who Would Be King
- ↑ The Man Who Knew Too Much
- ↑ Clap Your Hands If You Believe
- ↑ Our Little World
- ↑ No Rest for the Wicked
- ↑ The End
- ↑ First Born
- ↑ I Know What You Did Last Summer
- ↑ 11.0 11.1 11.2 Lucifer Rising
- ↑ http://featuresblogs.chicagotribune.com/entertainment_tv/2010/08/supernatural-season-6.html