Tomorrow marks ten years to the day since Castiel’s first episode of Supernatural aired. Here at Nerds and Beyond, we have been celebrating by posting an article each day leading up to the anniversary, highlighting some of the angel’s biggest moments. If you haven’t been following along, you can take a look here. It is almost inconceivable to look back at Castiel’s entrance ten seasons ago and see how far the character has come since then. He has learned a lot since he first became the Winchesters’ guardian, even if he did die a half-dozen times along the way.

In fact, at the beginning of Season 13, which is the subject of today’s article, Castiel is believed to be dead. Viewers have learned over the course of the last 13 seasons that death is not always permanent, but to the Winchesters, it is. They see Castiel’s wings burned into the ground and believe he is really gone this time. It takes a couple of episodes before Castiel returns to the boys, but because those first episodes deal with the grief of losing him, it feels to viewers as if he never really left.

Because this is Supernatural, he does not stay dead for long. Let’s start at the beginning of Season 13 and see how it happened.

Season 13, Episode 4 – “The Big Empty”

This episode gives us the answer to a question fans have been wondering for years: Where do angels go when they die? At the end of the previous episode, the Nephilim Jack seems to reach out to Castiel mentally, and we see him awaken, face down on the ground, looking into the vast nothingness of The Empty. In this episode, we see him wandering through the darkness aimlessly until he encounters a cosmic entity who has taken on Castiel’s form. It is surreal to watch two Castiel’s on-screen, looking identical but having two distinctly different sets of mannerisms, facial expressions, and voices.

The Entity explains to Castiel that he is the first angel or demon to ever awaken, which in turn woke him from his own rest. Needing Castiel to go back to sleep so that he can do the same, he asks Castiel why he woke up. Castiel believes that Sam and Dean must have made some sort of deal to save him, but The Entity explains he was here long before God, Heaven, and Hell, and there is nothing that has enough power to make a deal in The Empty except for him. Coming up blank as to how this is possible, from there The Entity painfully delves into Castiel’s mind in order to discover why he’s awake. Castiel asks The Entity what he wants from him. The Entity explains he cannot go back to sleep until Castiel does, helping Castiel to discover being awake causes The Entity pain. Even after The Entity tries to manipulate Castiel by showing him a highlight reel of his worst decisions and insisting there is nothing back on Earth for him, Castiel stands up for himself and declares he will stay awake fighting the Entity for eternity unless he releases him.

Not only is this a big moment because it is what leads to Castiel escaping from The Empty and joining Sam, Dean and Jack back on Earth, but it is also significant because Castiel doesn’t allow himself to be manipulated. Even after The Entity uses Castiel’s biggest weaknesses against him, telling him that the people he loves are not waiting for him and that he will only continue to be a disappointment if he returns, Castiel stays firm on his stance, knowing the Winchesters need him. This is huge, because unlike what has happened so frequently to Castiel in the past, he is not easily manipulated this time, and he stands up for himself instead of deferring to what somebody else wants. This marks the introduction of a stronger, more fierce, soldier-like version of Castiel, and it’s phenomenal to see him get his head on straight again.

Season 13, Episode 12 – “Various and Sundry Villains”

The last time we saw Castiel, he had gone to the angels to ask for help locating Jack. Unfortunately, the angels there trap him by holding an angel blade to his throat, and Lucifer, having just returned to our world from Apocalypse World, comes to his rescue. Lucifer tells Castiel about Michael’s plans and tries to convince Castiel to work with him and Jack to take Michael out. Castiel isn’t having any of it though, telling Lucifer he needs to talk to Sam and Dean before he agrees to anything. Sadly, before he can do that, Castiel and Lucifer end up captured and held prisoner by Asmodeus.

In this episode, we see the aftermath of Castiel and Lucifer locked up, and how the two of them are not exactly getting along. Lucifer tries to convince Castiel to give him some of his grace so he can restore some of his own powers and break them out of their cells, but Castiel refuses. He picks up on the fact that Lucifer’s power increases along with his anger, and uses that to his advantage. Proving just how strategic he can be when it is necessary, he irritates and insults Lucifer, goading him with stories all about how good and kind Jack is. This eventually causes Lucifer’s grace to power up in a fit of rage, and he is finally able to break through the wards keeping both himself and Castiel inside their cells.

Once they both break free, Castiel uses his grace to smite the demon who was keeping guard, and he and Lucifer escape outside together. After Castiel warns Lucifer that more demons will be coming after them, Lucifer tells Castiel once again that this fight would be much easier if he would just hand over some of his grace, trying to influence Castiel into trusting him by reiterating how they just fought side by side and it worked out fine. Instead of falling for it, we see Castiel stab Lucifer through the stomach with his angel blade.

Sadly, it does not work. Though Lucifer is in a weakened state, he still cannot be taken out with an angel blade. But the point, and why this is so important, can be easily summed up with Castiel’s words, “This is me, learning from my mistakes.” So many viewers were bloodthirsty for Castiel to get revenge on Lucifer for killing him, and there was something exceedingly satisfying about seeing Castiel stab Lucifer with an angel blade the same way Lucifer stabbed Castiel with one at the end of Season 12. This was one more step towards Castiel proving himself to be a smart and capable warrior since his return from The Empty.

Season 13, Episode 14 – “Good Intentions”

We see Donatello, the prophet, attempting to translate the demon tablet for a spell to open up the rift to the Apocalypse World. Once he finally figures it out, he brings the ingredients to Sam, Dean, and Castiel, where Sam is pleased to discover that they have most of the ingredients necessary in order to perform the spell, except for the hearts of two ancient warriors. Dean and Castiel travel there to collect them, and after they kill the warriors in battle, they are startled to discover that despite what Donatello told them, the warriors were not human and do not even possess hearts.

Now suspicious, Castiel and Dean return to the bunker only to find Sam holding an ice pack to his head after being knocked unconscious by none other than Donatello. Sam shows them a video feed of Donatello rambling to himself about power in the dungeon, and Dean fills Sam in on why they think Donatello set them up into a trap. Castiel watches the camera feed from the library when Sam and Dean try to interrogate Donatello, but quickly runs to Dean’s side after Donatello uses a spell to suffocate him. That spurs Castiel to enter the dungeon, and once he is finally clued in to the fact that Donatello doesn’t have a soul, Castiel explains that there is no fixing him from the evil that has infiltrated him and suggests that killing him would be kindest thing to do. When Sam and Dean don’t agree with that, Castiel makes a decision, causing another big moment for him.

Castiel locks himself in the dungeon with Donatello, knowing that while he gave them the wrong ingredients for the spell, he has the right ones in his mind. Castiel takes off his trench coat, spurring Donatello to tell him that he’s wasting his time considering Sam and Dean already tried to get information from him. Castiel says he is not Sam and Dean, and explains that he is going to do something he swore he would never do again and use his angel powers to strip the spell from his mind. While it sounds like a strategic move, Castiel lets the emotions behind his decision be known when he says, “I’m sorry, but I’m not going to let you or anyone hurt the people I love. Not again.”

This interaction between Castiel and Donatello is important because Castiel goes directly against the Winchesters’ wishes to do what it takes in order to get the spell. It’s a ruthless decision on Castiel’s part that renders Donatello brain-dead, but Castiel defends the decision by saying Donatello was lost to the corruption of the tablet anyway. Even so, it was a bold move to make, proving to us once more that Castiel has regressed to more of a soldier-like angel than we have seen him be since he first came to Earth to help Dean in Season 4. Regardless of the controversial choice he made, it was one that produced results, and at the end of the episode Castiel tells the Winchesters the ingredients for the spell they need to open the rift.

Season 13, Episode 19 – “Funeralia” 

In the bunker, we see Castiel, Sam, and Dean discussing their options for ways to hunt down Gabriel. They need him in order to extract archangel’s grace, which is an ingredient needed to open a rift to the Apocalypse World where Mary Winchester and Jack are currently trapped. Castiel suggests going to Heaven to ask them for their assistance, but Dean is against that idea, considering how the angels feel about Castiel. However, they don’t really have any other options, so reluctantly, Dean tells him to go for it, “just don’t get dead again” in the process.

Castiel arrives in Heaven to find it basically abandoned until he enters Heaven’s Throne Room, where he sees Dumah and two other angels. With the lights flickering around him, he explains the situation with Gabriel, Lucifer, Michael and Jack, asking them for their help. Dumah tells him they need to talk, and Castiel is forced to wait for what seems like a very long time. When Dumah finally returns to explain, she’s interrupted by none other than Naomi, who tells Castiel it is not that the angels don’t want to help him, it is that they can’t.

This entire encounter with Naomi is hugely significant, both to Castiel as an angel and to the story line in general. Before they get too far into anything, Naomi explains being alive by reminding Castiel that a drill to the head from Metatron isn’t exactly enough to kill an angel, and Castiel admits he was relieved to think she was dead. After she says almost flippantly that they never did get along, Castiel snaps, reminding her that she stole his memories, threatened to tear him apart, and made him repeatedly act out Dean’s murder. She shrugs him off, saying those were simpler times, and launches into the reason she was kept alive – because she had to be.

Naomi explains that the angels numbers have been dwindling for a while, and they are currently down to approximately a dozen angels in existence, including Castiel, and that all of them are required in order to keep Heaven running. They can’t possibly spare any angels to help Castiel search for Gabriel, but she does suggest that if Castiel is able to find Gabriel, he may have enough power to help restore Heaven. If he cannot, there is a good chance that the angels’ power will run out, Heaven will cease to exist, and thousands of souls will be returned back to the Earth, causing unbelievable chaos. Of course, this is a huge weight on Castiel’s shoulders, and now, as he has to save Mary and Jack, track down Gabriel, and defeat both Lucifer and Michael, Castiel is locked out of Heaven as Naomi closes the gates behind him.

Season 13, Episode 23 – “Let The Good Times Roll”

Season finales are often pretty intense, but this one takes the cake for one of the best in several years. In a nutshell, everybody from the Apocalypse World (save for Gabriel) is back in our world, and both worlds collide when Michael shows up inside the bunker. Sam, Dean and Castiel attempt to fight him off, but when that doesn’t go well, Sam prays to Jack, who has taken off with Lucifer to try to get to know his father better. As Michael continues to slowly strangle Dean, Jack appears, forcing Michael back and away from Dean using his powers. Michael complains to Lucifer that they had a deal, and Dean explains to a bewildered Jack that Lucifer made a deal with Michael so that Michael could rule the Earth as long as Lucifer could have Jack.

Lucifer denies the claims, but Jack uses his powers once more to force him to tell the truth, and just like that, Lucifer’s “good guy act” is over. In a fit of rage, he slits Jack’s throat exposing his grace and sucks down the majority of it. Sam hurries forward to help Jack, and after a burst of bright light, Lucifer, Sam, and Jack all disappear, leaving Dean and Castiel alone with a gravely injured Michael. Castiel asks the first question, which is the catalyst to everything that transpires from here on out: “How do we stop him?”

Michael admits there is no way. The good guys lost and the bad guy won. Dean insists that Michael can beat him, that he saw him do it before, but Michael explains it cannot be done with his vessel in this condition. It is too late. Dean is not about to take that as an answer, and drawing upon the knowledge he has about his own body and destiny, he offers himself up as Michael’s perfect vessel if he in turn promises to kill Lucifer. Castiel is understandably against this, and asks Dean several times not to do it, but Dean refuses.

Though we do not see the exact moment Dean says yes to Michael, the audience gets the chance to see Dean and Michael working together with Sam and Jack to ultimately defeat Lucifer… right before Michael takes over Dean’s vessel and flies away. From Castiel’s point of view back at the bunker, for all he knows, his entire family is gone and never coming back. He has no idea what happened to Sam or Jack, and with Michael taking residency in Dean’s vessel, he knows there’s very little chance of Dean coming back at all. The entire reason Castiel was sent down to Earth in the first place was to be the Winchesters’ guardian, and now, as far as he knows at least, he is left in their home without them. He couldn’t do anything to protect Jack from Lucifer, he couldn’t intervene in time to stop Jack and Sam from disappearing, and though he tried, he couldn’t get Dean to reconsider being Michael’s vessel.

When we see Castiel next, he’s sitting on the stairs in the bunker, shaking his head despondently in a silent answer to Mary and Bobby’s unasked question if any of them survived the battle with Michael. His anguish is written all over his face in a heartbreakingly sad expression, and though it is not a happy moment, it is undoubtedly a consequential one that Castiel is going to remember for years to come. Interestingly, Castiel did nothing wrong this season. He didn’t make any stupid choices, he didn’t work behind the Winchesters’ backs in order to protect them, and he wasn’t manipulated, but by the end of the season, he still feels as if he’s lost everything.

It is a little sad to end the last season recap article of Castiel’s biggest moments on such a low note, but maybe even more sad is that it is kind of appropriate considering Castiel’s time on the show so far. Though Castiel is a beloved character to many, he does not have a ton of cheerful moments for us to concentrate on. Life with the Winchesters is rarely anything as simple as happy, but based on what Castiel himself has said, knowing the Winchesters has been the best part of his life. And for somebody who’s been around for as many years as Castiel has been, that’s not a small declaration to make.

While that is it for our look back at some of Castiel’s biggest moments on Supernatural, this is not the end for our series celebrating ten years of the angel. We will be back tomorrow with one final article from some of our staff members explaining why we think Castiel is so important to Supernatural, and on a more personal note, why he is so important to us as people. You are not going to want to miss it!