Yeah. Just – just picture it. We ride to the rescue, save the day – make a great story. Look, the angels are like a big, dysfunctional family. We need to lock them all in a room until we work these problems out – all the factions, you, me–
After learning of Castiel from Kevin Tran, Metatron approaches his brother in an attempt to get caught up with what has been going on in Heaven since he was away. Metatron reveals to Castiel that from what he was able to piece together on his own, without the archangels running things in Heaven, it is open warfare with factions upon factions fighting and betraying each other to gain control. Castiel tells Metatron he is aware of what is going on, and blames himself for all the blood spilled. Metatron tells Castiel that Heaven still needs them, and proposes locking all the angels in a room to work their problems out, effectively shutting down Heaven.
Teleporting himself to a little restaurant in Ojai, California, Castiel quickly follows Metatron and questions what he means by "shutting down" Heaven. Metatron goes on to tell Castiel that much like the trials to close the Gates of Hell, there are trials to shut the Gates of Heaven. He says that he is not strong enough to go through the trials himself, and needs a warrior like Castiel to do them. Castiel agrees, feeling that he was the cause of the problems in Heaven, and that he should be the one to fix it.
Oh, you know, the trials -- God's little 'pull in case of emergency.' The Leviathans get out of control, you put them in Purgatory. Demons get a little too demonic, toss 'em into Hell. Angels get uppity, slam the pearly gates.
With Castiel on board, Metatron warns him he needs to understand that the tasks will be difficult. Pointing to their waitress, Jane, he tells Castiel that for the first trial he will have to cut out her heart, as she is a Nephilim. Castiel is apprehensive, telling Metatron that the girl is innocent and didn't choose to be a Nephilim. Metatron agrees, but asks Castiel which was more important: her life or his family?
Castiel and Metatron follow Jane on her way home. She stops and tells them she knows what they are, noting she could see their halos. She pleads with them, saying she only wants to live her life. But as Castiel advances, he regretfully apologizes, only to incite Jane's wrath. She easily overpowers both Metatron and Castiel. As she is about to show Metatron what an "abomination" is, Castiel is able to stab her in the neck from behind, killing her and completing the first of the trials.
Finding Castiel sitting on a bench, Metatron tries to assure him that they did the right thing, telling him the Nephilim was a monster. When Castiel asks him about the next trial, Metatron explains that a man in a bar across the street named Dwight Charles is to be struck by Cupid's arrow within 24 hours. He reveals that the next trial requires they retrieve "Cupid's bow." As they wait in the bar, Castiel attempts to expedite the process by finding a woman for Dwight Charles to fall in love with. But the sudden arrival of Naomi and her angels for Metatron throws a spanner in the works. Metatron willingly goes with them, leaving Castiel to finish the second trial without him. Seeking help, Castiel approaches Dean for aid, telling him he plans to shut it all down -- Heaven, Hell, everything. Dean agrees to help and joins Castiel at the bar, but they have no luck in finding a woman, until a beer delivery woman, Gail, enters the bar. Believing "Cupid" to be close by, they are surprised to learn that Gail is the cherub, and approach her behind the bar. Castiel attempts to use force to get the bow but Dean intervenes; speaking with Gail they learn that the chaos in Heaven has extended to Earth, as the cherubs no longer get daily orders. Trusting that Castiel can fix things, she freely offers up her bow, which Castiel removes from her body.
In Heaven, Naomi extracts information from Metatron's mind, learns of his true intent, and questions his motives. Metatron tells her it is simply payback for having been run from his home and the archangels refusing to acknowledge what God left them. Naomi teleports back to Earth in an attempt to appeal to Castiel to stop the trials, telling him of Metatron's motive of revenge. Not believing Naomi, Castiel continues on his path, going to Naomi's office in Heaven to find her with a drill in her head. He is ambushed by Metatron, who straps Castiel to the chair. He reveals that there were never trials, and that they have been gathering the ingredients for a spell, with the final piece being grace which he steals from Castiel. Having rendered him human, Metatron tells Castiel to go live a full life on Earth and when he dies, to come find him in Heaven and tell him his story, before sending him back to Earth.
Angels. They're falling.
In the Bunker, as Kevin is about to leave, the various machines begin to turn on by themselves, a warning alarm goes off, and the world map begins to light up. As Castiel regains consciousness on a hill, he looks up to see the angels being ejected from Heaven. After preventing Sam from completing the demon tablet trials, Dean and a dying Sam exit the church to find the angels falling. They witness one angel's wings burning off its vessel as it crash-lands in the nearby river. The next day, as Sam is being treated in a hospital, Dean notices the news reporting the angels falling as a “Global Meteor Shower.”
In the aftermath of the Fall, a host of angels were killed when they were ejected from Heaven, their bodies becoming shredded by the Fall. Wings were destroyed, leaving only vestigial limbs with clumps of feathers incapable of flight, while other angels had their wings completely burned away. Castiel became a fugitive, blamed for his unwitting part in the expulsion of the angels, and was pursued by various factions of angels, as well as rogue reapers under the employ of Bartholomew.
Castiel, the angels... Our numbers were greatly diminished after the Fall. No one's made new angels since the dawn of creation. We're going extinct. You would need a powerful force to make more of us.
After finding vessels, angels on Earth begin forming factions once again, leading to another civil war, where even more angels could perish. Not long after taking over Heaven, Metatron begins to find his solitude tedious and approaches Gadreel with an offer to help him rebuild Heaven. He sends Gadreel out with the Horn of Gabriel, which he uses to draw angels to him. The gathered angels are given an offer to join with Metatron, and those that refuse are slaughtered. Eventually Castiel's hand is forced and he takes on a leadership role among the angels, by consolidating various factions under him as they hunt for Metatron.
Metatron is able to sway the angels to his side, offering them entrance into Heaven if they leave Castiel's cause. Metatron's leadership of the angels proves to be short-lived when Castiel is able to broadcast through angel radio Metatron admitting to "playing" his brothers and sisters, and he is soon locked away in Heaven's prison. In the aftermath, the angels begin to govern themselves via committee, rebuilding and reorganizing Heaven along with lots of reconciliation and their new leader eventually became Hannah, who restored order in Heaven until her death at Efram's hands.
However, with the Fall and various disputes amongst the angels, the angel's numbers were greatly diminished, to the point that by May 2018 there were only nine angels left in Heaven and one or two wandering on Earth, including Castiel, Naomi, Indra, Eremiel, and Dumah. The remaining angels sequestered themselves in Heaven to ensure that it would continue to be powered, to prevent billions of souls falling to Earth if Heaven should shut down. It's later revealed that Jack Kline is capable of turning humans into angels by forging human souls into angelic grace. While working with Dumah, he uses his powers to transform members of a prayer group into angels.
- While Metatron was not truthful with his intent, he did not exactly lie to Castiel as he told him in 8.22 Clip Show:
"Angels get uppity, slam the pearly gates."
- Only leaving out which side of the gates the angels would be on.
- As the angels fell, the map in the Men of Letters Bunker began to light up revealing a majority of the angels appeared to have fallen in and around Europe and the Middle East.