[Warning: The below contains MAJOR spoilers for the series finale of Arrow, "Fadeout."]

R.I.P. Oliver Queen.

The hero TV needed and deserved has left the building. It's the end of an era for the Arrowverse as O.G. action-drama Arrow has just wrapped up eight seasons of leather costumes, deserted warehouse battles, and fandom feuds with a lump-in-your-throat goodbye episode full of guest stars and new starts for those Ollie left behind.

Framed in part as a return of the "Emerald Archer" documentary team that filmed Team Arrow for the 150th episode (led by director "Marcia Pedowitz" in a salute to CW head Mark Pedowitz), the hour served as a beautiful coda to a story that actually ended when Stephen Amell's Oliver sacrificed himself to save the universe from the Anti-Monitor during January's Crisis on Infinite Earths crossover.

But even with some time between that tragedy and the finale — the show leapt right into the future for a post-Crisis episode that tee'd up a possible Green Arrow and the Canaries spinoff for Katie Cassidy (Earth-2's Laurel Lance), Katherine McNamara (Mia Smoak) and Juliana Harkavy (Dinah Drake) — the struggle was still real for Diggle (David Ramsey), Sara Lance (Caity Lotz), daughter Mia, son William (Ben Lewis) and, well, almost everybody they fit into the production schedule. According to executive producer Marc Guggenheim, who expands on what we saw in the Q&A below, there was no shortage of actors ready and willing to hightail it to Vancouver for the finale.

And not only did the writers squeeze in a ton of cameos that actually meant something, they also made sure to take care of the regular cast. Original series regulars Ramsey and Cassidy, in particular, were given spectacularly emotional material (including a possible future in the Green Lantern Corps for Digg), and fan favorite Emily Bett Rickards made her long-awaited return as Felicity to bury her husband, help the team find her and Ollie's kidnapped son, and come face-to-face with Mia, her now-grown daughter from the future.

See Also We Have Questions! Marc Guggenheim on the 'Crisis' Cameo & Casualty The EP talks last night's big death (why now?!), how that cameo came to be, and what's in store for Emily Bett Rickards' return.

In the end, everyone wound up OK... especially Felicity, who was finally reunited with Oliver in a full-circle sequence that brought back a familiar red pen and promised the couple a happily-forever-after. As far as series finales go, this one hit pretty much the bullseye. So goodnight and thank you, Oliver Queen. You have done good...without fail.

OK, I just watched your finale...

Marc Guggenheim: Be honest with me, because you know the Internet will be. [Laughs]

I think you stuck the landing. You got so many people back... opening with Moira (Susanna Thompson) was just awesome. There's so many characters and friends of the show that you had and they didn't feel just stuck in. They all had a reason to return for Oliver.

Yeah. I think there were a couple of people who were not available to us. I would have loved to see Jessica De Gouw (who played Huntress) back. I would've loved to see Colin Salmon (Walter). There was a list of people we tried get and most of them were filming television shows! [Laughs]. Some, in the case of Jessica, were filming movies. Katrina Law barely happened because she was shooting Hawaii Five-O. In fact, we actually started shooting the funeral while she was on the way from her airport. So there were some that literally happened by the skin of our teeth.

You got Grant (Gustin) and Melissa (Benoist), Colton Haynes, Willa Holland... you even got Ragman back!

Joe Dinicol, who plays Rory, is kind of like Jessica De Gouw to me in the sense that there are these characters who you're always trying to get back on the show. “Oh, I'd love to revisit this character. Let's revisit this guy's character.” And then you can't make it work either because the story's not right or the timing's not right, so I'm really, really glad we got Joe back. Because he's a beloved character for us and Joe's just a wonderful guy. And again, another guy whose schedule we had to work around because he was shooting, ironically, the series finale of Blindspot. So, yeah, none of this was easy. And I've got to give major props to [showrunner] Beth Schwartz. I was so consumed with the crossover and quite frankly so burnt out about trying to organize cameos and stuff for Crisis, that she really picked up the baton. She was on the phones to the agents and working with the line producers to make everything possible. And finding the money to pay people. Because actors, they don't work for free. So she was the real hero.

And I'm just assuming John Barrowman didn't want to dye his hair back to play Malcolm.

[Laughs] No, Barrowman actually was shooting something or was in a play. He was also one of the first people we went out to. In fact, we actually went out to him very early on once we knew when the finale would be shooting, and he was committed to something in London for over a month. So, again, another great example of people we would have loved to have brought back.

When we spoke right after the crossover, you mentioned that you realized the finale should be about Oliver saving his city and honoring that. Why introduce the case of young William's abduction on top of that? Was that because of that family element?

It's funny, that was actually an idea that came out of the writers room. The writers pitched the idea and originally we weren't going to have a "case of the week," but the reason that pitch resonated with me was twofold. Number one, because spoiler alert, adult William is kidnapped in front of Mia [at the end of the Canaries backdoor pilot] so there was a nice parallel there. She's dealing with the consequences of that abduction and this feels like the future coming back to haunt her in a way. And the other piece was, we always knew that we wanted to honor the flashback convention in the show, as well as the first season of the show, that kicked all this off. So this gave us a flashback story set in Season 1. We talked about a lot of different ways of connecting that flashback story to the present day. But when the writers pitched me the idea of William being kidnapped, I thought, "Oh, what if he's kidnapped by the guy that Oliver takes down in the flashback story?" And then the past and the present are talking to each other, so it just made sense.

And how did you pick John Byrne, the flashback villain?

We ended up coming up with a brand new villain, because Oliver pretty much killed everybody on his list in Season 1. All things being equal, it would have made a lot of sense to bring back Adam Hunt, the villain, from the first episode. But we killed him off Adam Hunt!

OK, because I feel like a lot of people were scouring to find John Byrne as a bad guy from the show's past!

And he wasn't! [Laughs] When I sat down to write that, I basically just picked a name out of the notebook, one that we hadn't crossed off. John Byrne—who's a very well-known comic-book writer and artist—is someone I've always wanted to namecheck, even though John doesn't really have a connection to the Green Arrow character. I'm just a big admirer of John's work and I just thought, "You know what, this is my very last opportunity to do it." So I did a little retcon.

So that was all new footage then?

The whole flashback is.

Including that fight sequence?

Everything. The only thing that Stephen is in that was not shot for the episode, was the very beginning with him knocking out Slade (Manu Bennett) and saving Moira. I can tell you how that came about. When we start talking about the finale in earnest, I asked our post-production team to put together a reel of all the deleted scenes we've ever had on the show, including the ones that have not been released. And episode 223 originally began with a dream sequence of Oliver basically imagining, "What if he was able to save Moira's life?" But we couldn't include that in the final cut of 223, so I had this footage and was like, “Oh, this is the perfect way to open things because it illustrates how things unfolded differently in the post-Crisis world!" It was this wonderful happy accident. The part with Mia dreaming of the moments from the pilot where Robert kills himself, that was originally supposed to open the finale. It all just came together in a nice way and it was great to see Manu again as Slade Wilson. And like I said, it really illustrated how different the world was. It was just a wonderful little discovery.

The epic fight sequence that you had leading up to the John Byrnes showdown...I feel that may have been your longest fight sequence ever.

It was. The raison d'etre of that was, "This is our very last fight sequence so let's leave it all on the field. Let's go out with a bang. Let's just go nuts." That was the gauntlet we threw down at James Bamford and his team. And they absolutely delivered in spades. That was shot over the course of I think three separate nights. It was easily our biggest sequence. When I delivered the cut to the studio and network, in the middle of the sequence I had post-production chryon over it "In seven years the show has never been nominated for a stunts Emmy."

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That's exactly what I was thinking during the scene!

What do you have to do? I mean, I'm not even asking for an Emmy. Just a nomination.

You guys should have been nominated for that freighter fight sequence when Slade kicked the guy and then punched him in mid-air.

Episode 215! I know. I know. It is maddening to me. It is maddening for me. So anyway, that is us going out big, it's the very last one we're going to get a chance to do and we do it better than any other superhero show out there.

What was the most emotionally difficult scene for you guys take to get in?

Emotionally difficult? Probably the funeral, the eulogy in particular was tough. I found that hard to write, mainly because of two things. Number one, we hit upon this idea of an intercut with the eulogy and seeing everybody. So of course, it's got to do two jobs: It's got to work as the eulogy, but it's also got to work with the images that you're seeing played against it. That's one number. Number two was like, "What is there left to say? What is there left for Diggle to say about this character?" And for me, the piece that unlocked it was taking the familiar phrase of "Oliver became something else" and turning it on its head. Turning it away from what we all assumed it to be, which is the Green Arrow, and making it about what Diggle knows, which is that Oliver Queen became a better man. A better Oliver Queen.

Which was all we were rooting for him to become.

I think the thing that I've loved so much about this show is how flawed Oliver is. He's a very flawed hero. He starts off a spoiled rich asshole. And in the process of those first years, he makes these terrible decisions. He does some truly horrible things. At the end of season three for example, he tortures a man and enjoys it. And I love the fact that for me, Oliver was never fighting bad guys. He was always fighting his lesser demons. And by the end of the show, he's a father twice over, he's a husband, he's a hero, he's not living in the shadows, he's out there as a public hero. He's been a Mayor and he's been the leader of this team. And we make the point a lot, probably too much, that Oliver never set out to do this with a team. But he evolved his mission, the same way he evolved his character.

And that is probably for me, the most important thing about the show. Whenever we were breaking episodes, all 170, we would always speak in terms of, "What is Oliver's journey in this episode?" And I think if you watched the series finale and you watch the pilot, you see Oliver didn't just have a journey per episode. He had a journey for the entire series. And even though we always knew from jump that his journey would ultimately end in death, I think the more fulfilling thing is that before his death, he figured it all out. He became the best man possible.

What was Emily's return like? Obviously, everyone wanted that.

I think in many ways it just felt right. I was there on set for all of Emily's scenes and honestly, it just felt like she'd never left. And I think that's the way her performance felt. The way she and the other cast members interacted with each other, it just felt like we were picking right back up, that, that she had been in episodes 801 through 810. And that was really, really great. That very last scene was in fact the very last season shot.

Oh, geez.

Yeah. And by the way, and what was great was we were shooting until one in the morning, it was the end of the shoot, and Juliana [Harkavy, Dinah] was there, Colin Donnell [Tommy] was there. All of these cast members came out just watch Stephen and Emily film their last scene and the show's last scene. It was really, really nice.

See Also Inside Secrets of the 'Crisis on Infinite Earths' Arrowverse Crossover The powers that be from 'Arrow,' 'The Flash,' 'Legends of Tomorrow,' 'Supergirl,' and 'Batwoman' gave reporters inside scoop on the first episodes.

It was so lovely. Even when you realize," Oh my God, Felicity's now dead... guess we won't be seeing her on the Canaries spinoff."

[Laughs] Well, let me put it to you this way: All things are possible. The one thing I've said to all the actors who we've killed off over the course of eight years, and this is proven to be true time and time again, is that death on this show does not mean goodbye. I mean, look at Colin Donnell. He has been on the show so much. So no one has ever truly gone. And if Green Arrow and the Canaries goes, there is already a host of different ways to have Emily return. I actually have a very specific one in mind, but I'm obviously not going to tell what it is, because maybe we'll get it. Maybe we'll get a chance to do it. I don't know.

And what about Diggle? Ramsey was so great in all of these final episodes and you tease that Digg and Lyla are moving to Metropolis. Is the plan for him to actually show up on Superman and Lois?

I don't know exactly what the plan is just yet. David and I and Greg [Berlanti] have all had a lot of conversations about David and Diggle's post-Arrow future. We've got some ideas that I'm incredibly excited about. But as a general rule, I try to avoid speaking for shows that I'm not involved with.

And that Green Lantern bit... I mean it's not even a nod. That was literally a Green Lantern origin moment.

[Laughs] I have a variety of different corporate partners I have to work with, so I am going to leave it to all of your interpretations as to what that scene was all about. All I can tell you is that this was a moment that we've been discussing for years. About a year ago, we got approval from DC Comics to do this moment and in my mind, it always belonged in the series finale. Again, we wanted to hint at what the life for these characters is after the show ends, because their lives do not.