SPOILER ALERT: This story contains details of tonight’s episode of Arrow

EXCLUSIVE: An old friend of Oliver Queen’s showed up tonight in Star City to help bring a deceased soul back from beyond. With that mix of the mystical and the bow, the introduction of John Constantine to Arrow is yet another reach into the greater DC Universe that the Warner Bros TV-produced show is making. However, unlike the introduction of The Flash and what will soon be the Legends Of Tomorrow, Constantine showing up on Arrow is more of a rebirth. The Alan Moore co-created demon hunting character from the classic Hellblazer comics saw his own NBC series formally cancelled earlier this year after 13-episodes and no traction in the ratings.

I spoke with Arrow EP Marc Guggenheim, who developed the CW series with Greg Berlanti and Andrew Kreisberg, about tonight’s “Haunted” episode and how they were able to pull it off once they got the corporate green light to bring Constantine back. We also chatted about whether the Hellblazer will be back, his role in the Stephen Amell-played Arrow’s backstory and the leaking of the episode earlier this week. With air dates of December 1 and 2, Guggenheim revealed how this year’s Flash and Arrow crossover is going to be different than the first one and the role Legends will play. And yeah, there’s a certain Dark Knight mentioned too.

DEADLINE: So Marc, let’s cut to the chase – are we going to see more of John Constantine in Arrow?

GUGGENHEIM: There’s no plans. This was always designed to be a one off.

DEADLINE: Well, OK, I’ll take that but it would be great to see the Hellblazer back. Now, with his current appearance on Broadway in Thérèse Raquin with Kiera Knightly, how did you pull off getting Matt Ryan on the set up in Vancouver?

GUGGENHEIM: I’ll tell you, to be honest with you, it was tricky because of the play. The play created a variety of scheduling challenges and believe it or not it was starting to look as if we wouldn’t be able to get him or we would only be able to get him for a day. It definitely posed a challenge.

DEADLINE: So what did you do to pull off the Constantine episode and shooting it in August?

GUGGENHEIM: Well, it occurred to us that we’ve got the scripts for Episodes 4 and 5 already written. I went to Greg Berlanti and I said, “So I have a crazy idea for how to make the schedule work,” and I think his response was something along the lines of, “You’re right. That is a crazy idea.” But if we were to switch the production order of the episodes and have Episode 5 shoot in Episode 4’s slot and Episode 4 shoot in Episode 5’s slot then we actually could shoot with Matt as much as we wanted to, so we did.

I have to give a lot of credit to the cast because it’s not easy to act out of order. And a lot of credit to our amazing crew too who really rolled with the punches. But it worked out beautifully and I couldn’t be happier with both episodes, quite frankly.

DEADLINE: Besides the rescue of Sara from what essentially seems like Hell, there is a lot of backstory in the Haunted episode like how Constantine and Ollie met on Lian Yu island that plays such a big role in the show and how Constantine used magic to give Ollie that tattoo of Chinese characters that’s on his torso…

GUGGENHEIM: That was something that writer Brian Ford Sullivan had pitched us with this episode. Originally our intention was to do something different with the tattoo. We were actually going to reveal something completely different, non-mystical about the tattoo last year with the Hong Kong story line.

It’s funny, even though we do 23 episodes a year, you would think our biggest problem would be filling up those episodes. We actually have the opposite problem, which is a lot of ideas don’t make it into a given 23-episode season. So the question of the tattoo was sort of lingering out there, something that we had to cover, and Brian came to us with this really terrific pitch. We instantly loved it and you haven’t seen the last of that tattoo playing an important role in Season 4.

DEADLINE: And using the island as the flashback backdrop seems very deliberate and having Ollie and Constantine going down to that crypt, is it?

GUGGENHEIM: Yes, Haunted allowed us to also get out a bit of exposition about the island. It’s very subtle, it’s buried in there, but it’s really, really important. By having Constantine in the flashbacks we actually had a character who could get out an important piece of exposition about the nature of the island that does explain why the events that we’ve been seeing on the island have been transpiring. It was all just everything very organically all coming into place.

DEADLINE: One thing that did not organically come into place, and I say this as a huge fan of the Hellblazer comics, is NBC’s Constantine series, which started soft last fall and never really recovered. Why do you think the Constantine TV series failed?

GUGGENHEIM: There’s so much television out there, there’s so much content between network, cable, and streaming, that it’s very, very hard to make a noise in this environment. I’m sure that their Friday nighttime slot didn’t do them any favors either. But there’s so many wonderful shows that just don’t find an audience and they have nothing to do with quality.

DEADLINE: Constantine is back with a new comic series now, I know you’re a big comic fan so did you take a look at that for this episode?

GUGGENHEIM: You know, I’ll be totally honest with you, I should say yes because that’s what one says when one is asked these questions, but in all honesty I have not had a moment. It’s been such a struggle to find free time with Arrow and Legends on my plate that I have a stack of comic books on my desk that is like, a mile high, and Constantine is in it, but you know, I’m basically trying to get to Christmas in order to have time to catch up on all my reading.

DEADLINE: In terms of catching up, earlier this week, the Haunted episode got leaked online, what do you think of that and what the impact will be?

GUGGENHEIM: Obviously we’re not thrilled about it. You try to make yourself feel better by saying that there’s no such thing as bad publicity, but this is obviously not how we want people to experience the episode. Particularly since it was pirated off a screener copy without finalized visual effects, sound and color.

That said, I don’t think — knock on wood — it will affect our ratings. Arrow had traditionally been one of the more torrented shows out there and it hasn’t affected us before. Fingers crossed.

DEADLINE: Constantine isn’t the only crossover you guys have in your quiver, there’s another Flash crossover coming in December plus obviously the new Legends Of Tomorrow. How will this year’s Arrow/Flash crossover differ from the first one?

GUGGENHEIM: There’s a lot of things that are really cool about this year’s crossover, one of which is the fact that there really is a true 2-part story unlike last year where it was two interconnected episodes where each had their own beginning, middle, and end.

This is a big two-part event, one single bad guy, and it will very clearly launch Legends Of Tomorrow. But at the same time what I think is a lot of fun about it is that it doesn’t feel like a backdoor pilot for Legends Of Tomorrow. It feels like an episode of Flash and then an episode of Arrow. It truly is a 2-hour Flash/Arrow event that just so happens to introduce us to some new characters who will be a big part of Legends Of Tomorrow.

DEADLINE: There’s been a lot of appearances from the great DC Universe in Arrow, obviously Flash, Legends, Black Canary now part of the crew but who is your dream DCer?

GUGGENHEIM: You know, I love Batman. He’s probably my favorite DC character and of course I’d love to see him on Arrow, but you know, that’s just not in the cards anytime soon. So it remains a fantasy, but we have so many other fantasies and pipe dreams of ours have come true, I really have no complaints.

We always say we never set out to introduce this many DC characters, you know, on the screen. Even by the end of season one of Arrow when we had done Deathstroke much sooner than we planned, we had never planned on doing Huntress, we didn’t plan on introducing Roy Harper so soon. You know, that was all just in Season 1. To look at where we are now, you know, four years, two going on three shows in, it’s like, how did this happen? And we’re always pinching ourselves.

DEADLINE: Do you feel that way looking at Haunted and the appearance of John Constantine now?

GUGGENHEIM: One reaction is that when I saw the episode all cut together it felt to me like this is a crossover episode of Arrow and Constantine. It just so happens we’re not crossing over in the other direction as well. And then my second reaction is wow, that’s really cool.

The God’s honest truth, I think if you were to ask Greg or Andrew, they would tell you the exact same thing, when we do something like this, or when we do the Flash/Arrow crossover, or we do Legends Of Tomorrow or any of these things …every time, quite frankly, that we get a chance to realize these comic book characters in a new way, or bring a new character onto any of the shows, the 10-year-olds in ourselves giggles and gets this little jolt. And we really felt that doing this episode.

That’s fundamentally the reason why we do this because we don’t have to be producing superhero shows. We really do it for the love of the game, and you know, when you get a chance to bring a beloved character played by a beloved actor off of a beloved show into this little world you’ve created that’s really, really special.