The revelations and teases we've seen for the fourth season of "Arrow" have already promised to place a lot of new bolts in the show's arsenal. But now, Executive Producer Marc Guggenheim offers a deeper peek into the quiver -- including some pointed info about the show's forthcoming sister series, "DC's Legends of Tomorrow."

Constantine's "Arrow" Appearance Tied To White Canary's Return

At The CW's summer party for the Television Critics Association, Guggenheim joined CBR News and E! Online for a revealing round of questions focused on the extensive string of casting news coming out of the series lately and confessed that the upcoming spinoff series is "the craziest show I've ever been involved with."

[Editor's Note: At the time of this conversation, news of Matt Ryan's guest stint as John Constantine had not been announced]

The news that broke today about casting Oliver's past love interest, Elysia Rotaru...

Marc Guggenheim: I got a lot of Tweets on my timeline. People tagging me, saying basically to people who were upset, "Read deeper into the article." A lot of people didn't get to the "flashback" part and they lost their minds.

How much do the show's 'shippers influence you, cause you to reconsider whatever relationship plans you might have cooking?

Ooh, I love these questions, because what's great about that question is, there's no good answer. There's no answer I can give that won't get me in trouble. The only thing I can say, or the only thing I'm willing to say, is that we did not get Oliver and Felicity together because of the 'shippers. That, quite frankly, we did that because of the chemistry between Emily and Stephen, and we kept writing towards that chemistry.

And then we reached the point where we were like, "Wow, we're writing towards it. We've got to pick a horse -- or not pick a horse. We've got to do something here. Either that relationship is going to go forward or it needs to stop." But it really was -- we wrote to what we were seeing on the screen in the dailies. And I know there will be some people who are upset with me. But at the very least, it has the virtue of being true.

I mean, Felicity was never part of the original plan of the show. She was supposed to be a one off. Had we cast anyone other than Emily Rickards, she would have been a one off. And we wouldn't be having this conversation right now. But one of the great things, I feel, about television as opposed to a feature is you have an opportunity -- week in, week out -- to respond to what your actors are giving you.

I mean, we write so far ahead of broadcast, particularly in the first half of the year, it's impossible to respond to the fans. It's actually one of the frustrations we have. We're doing stuff now. We don't know what's going to play and what's not going to play. The only thing we can respond to is what we're seeing in the dailies. And you write towards that, or you write away from that, depending upon what's working and what's not working.

Let's talk Rutina Wesley -- that's a good get!

She's a wonderful get, and I want to say publically: God bless her! We had some scheduling issues. She was really flexible, and she really did us a solid here. And we're incredibly excited. Everyone moved heaven and earth to make the scheduling line up, and it's going to be awesome. I'm really excited about the character she's playing, and I'm excited about the storyline that we've got planned.

Any teaser? Is she from any comic book source?

Her character is named after a character called Lady Cop, who is a lady cop. We're just using a character name, Liza Warner. We're not going to call her Lady Cop, but she will be a female cop.

Can we talk about the flashbacks? Are we going to see some comic book heroes in them that have a tie to the present day?

Well, I'll tell you, one of the things that we're trying do with the flashbacks this year is, we want the flashbacks to tie into the present day in a different way than they typically have in the past. In the past, it's always been someone from the -- in previous seasons -- from the flashback showing up in the present day. And we're going to try to create a different kind of connection between flashback and present day story, rather than go to that well all the time.

Anarky will be appearing, the latest example of a character brought over from the Batman mythology. How much fun is it be able to do that, given that in the comics Green Arrow doesn't have the deepest bench of villains?

I will say that Green Arrow doesn't have a villain's bench. At best, they have a villain's love seat. It's really small. And big props and thanks to Geoff Johns, who sort of manages the DC properties and sort of tells us, "Hey, this person's available. This person's not," for getting us Anarky. Because it's hard. Basically, Green Arrow's got, like, maybe Merlin -- used him. And Vertigo -- used him twice. So we really have needed access to the other DC characters.

And Anarky, he's a fan favorite, actually, of a lot of the writers on the show, including me. If you actually even go back to episode 1.18 of "Arrow," we had a graffiti on the subway. And as the subway comes towards the camera, you see it's the Anarky symbol. So this character's been someone who we wanted to use for a while, and we're really excited.

How are you tweaking him for the show?

The take is very similar to Arrow. We wanted to see the evolution of a bad guy, the evolution of a villain. A lot of times on our show, the villains sort of come to us pret a porter. They're fully formed. This is a little bit more of an origin story, and that's why we have Alex [Calvert] booked for multiple episodes, because we're going to see the evolution. When you first see Anarky in episode 4.02, Anarky is not Anarky. He's Lonnie Machlin from the comics. And you'll see the events that will lead him to become Anarky. We wanted to really play out that origin story.

We haven't seen any long-term effects for Thea coming back from the dead yet. How are we going to see her being affected?

We're really getting into that in the first half of the year. We're going to face it head on, and you're going to see it very directly. And it's become an important story point as we move forward. And then the explanation of why we haven't seen anything since 3.20 until Season Four will also be explained.

How does the new love interest for her [Parker Young as Alex Davis] play into that?

I would say it complicates things a great deal.

How will her journey out of the Lazarus Pit differ from the White Canary's?

There will be some similarities because they have some very obvious parallels. They were both in the Pit, so they're going to be dealing with similar consequences. At the same time, one was dead and the other one wasn't. So it's not an apples-to-apples comparison, but there's definitely some points of comparison the two of them will have.

"Legends of Tomorrow" looks like it's going to be the most "comic book" of all the shows because you have access to your universe, the DC canon, time travel -- and you can just mash it all up.

I have to be careful, because the nature of the Internet is, "Marc says that all the DC characters are fair game on Legends!" And then I get an angry phone call. I will say that it's certainly the craziest show I've ever been involved with. I mean, the show is nuts. It's got time travel and superheroes and super villains. It's a great deal of fun. And we always try to write and produce these shows for people who love the comics but also for people who don't read comics.

And I think the challenge of the show is -- and we said this with "Arrow" back four years ago -- we know people who love the comics and who are going to want to see the show. No one's ever done a superhero team-up show on television before. So I figure they're okay. We also have to make sure that people -- what makes "Flash" and "Arrow" successful is because it appeals to people who don't just read the comics. And "Legends" has to attract that same non-comic book fan audience.

What prompted going with villains alongside the heroes?

I think it's a combination of a couple things: first of all, when you've got Wentworth Miller and Dominic Purcell and you don't use them, that's, like, criminal. That's really what's criminal. Like, you've got to make use of those guys. But also, it's the virtue of having these X factors, these monkey wrenches in the works. It makes the whole situation very unpredictable.

And the show is so much richer for having these two guys in this group of superheroes. It's almost like, if you did Avengers but you made Loki an Avenger. Can you imagine how much fun that would be? And that's what it is. It gives you so much more story to tell. So you've got great actors, and you get a chance to use them in a way that is so interesting and so challenging.

You've got their new "Prison Break" schedule all worked around yours?

You know what it is. I know what our production schedule is, and I assume that the Prison Break's been handled. I'm a huge "Prison Break" fan. I'm thrilled. I can't wait.

How ambitious are you guys, as far as the amount of shows you might want to have on the air at any given time?

Well, I can only really speak for myself, and the fact that I'm only involved with two of the many, many, many shows. So I'm comfortable. I'm working hard, and I don't sleep a lot, but I'm comfortable. The thing Andrew [Kreisberg], Greg [Berlanti] and I are always saying is: each of the shows just has to feel different. That's the most important thing.

It's like, what's great about "Flash" is it's very different from "Arrow." No one's going to tune into "Flash" thinking that they're watching an episode of "Arrow." Similarly, no one's going to tune into "Legends" thinking they're watching an episode of "Flash." So the shows just have to feel different and be different. And then, it's up really to the audience to tell us how much is too much.

Is there something that you've learned from "Arrow" that you're going to apply to "Legends"?

That's a great question. In the case of "Legends," it's particularly true. There's a lot of, like, production tricks and stuff that we've learned that we apply, but you can do all these things to make the shows look epic and be amazing and feel like little movies. But if the characters aren't coming across as characters, if it's just gimmicks and plot, the audience tunes out.

Like, on "Legends," they'll come for the spectacle and fun of seeing all these characters on the screen together, but they're going to stay because we have the likes of Victor Garber and Wentworth Miller and Brandon Routh and everyone bouncing off of each other, and getting to know those characters.

Any comic book work ahead for you?

Yes, thank you for asking! I've got a few things. Thank you, I can always count on you! Right now, I'm writing "Agents of S.H.I.E.L.D.," something that can only happen in comics, for Marvel, and I'm really having fun with that. Actually, I came up with what I thought was the coolest twist. I wanted to come out of the gate with something really surprising and just a dynamic you would never expect. And I wrote it. And then I got word that actually, "S.H.I.E.L.D." was doing it on the show, so I had to change it! So I'm doing that.

I've got two creator owned comics coming out. I've got one called "Stringers." "Stringers" is a comic book about video freelancers. Kind of like the movie "Nightcrawler" but nothing like the "Nightcrawler" because it's funny and a thriller. It's everything "Nightcrawler" isn't. And that's for Oni Press. It's coming out August 26.

And then September, from Legendary, I have "The Infinite Adventures of Jonas Quantum." And Jonas is like a new kind of hero. He's basically like I'm trying to create a new James Bond, a new Indiana Jones, a new kind of superhero -- this superhero, whose super power is he's the smartest guy in the world. And I just turned in the script for the fifth issue, and it's easily, of over ten years of writing comics, the craziest issue I've ever written of anything. So I'm very excited. I was really proud of it because it's like, "Okay, this is completely insane." And I think it's going to be great.

"Arrow" returns Oct. 7 to the CW, while "Legends of Tomorrow" premieres in 2016.