SPOILER WARNING: The contents of the following article contain plot points from today's "Brightest Day" #24.

Last week, readers of the DC Comics Universe received a long-awaited shock when the publisher brought former DC mainstay Swamp Thing back from its Vertigo imprint to mix it up with its core superheroes as part of the plotline for year-long event series "Brightest Day." Today, the final issue of the 24-part series ships to comic shops, and aside from providing a wrap to storylines with a wealth of resurrected DC heroes, the series contains one more big twist.

As part and parcel of "Brightest Day" #24's rollout, John Constantine - the smarmy British occult detective created by Alan Moore, Steve Bissette and John Totleben as part of their classic "Swamp Thing" run -also returns to the DC Universe proper. Of course, Constantine remains the star of the long-running Vertigo series "Hellblazer," currently written by Peter Milligan and still digging into the kind of urban horror the mature-readers Vertigo imprint has always been known for.

With the long-standing wall between Vertigo and the DCU now seemingly crumbling away, CBR News spoke with DC Co-Publisher Dan Didio about exactly how the return of these characters to DC books proper will play out both in "Brightest Day" and into incoming stories like "Brightest Day Aftermath: The Search For Swamp Thing." Below, Didio explains DC's reasoning for bringing the characters back to their origin point and how that move doesn't shake up the work still being done at Vertigo.

CBR News: Dan, first it was Swamp Thing and now Constantine. Overall, bringing these Vertigo characters back into the DCU is something that I think I've seen fans ask after at conventions more than almost anything else in DC's cosmology. Who led the charge and stood up in the past year to say "We need these characters back in DC books," and why did you think that was a good idea?Dan Didio: It was a constant discussion we'd been having. This is something that Geoff [Johns], Jim [Lee] and myself have been talking about since we first took our new positions with DC. It was always an interesting discussion for us because there were so many exciting and important stories with Swamp Thing in the day that were associated with the DC Universe that we thought of fondly. And we understood why there was a distinction between the DC Universe and Vertigo, but since some of these characters actually started in the DC Universe, we didn't understand the reason why we shouldn't be able to migrate them back at a particular point.

That was the primary goal, though what happened was that Constantine fell into a rather strange zone. When you look at Swamp Thing and all the big stories you think about with that character, John Constantine is an integral part of those things. But we have a very long-running and very successful series in "Hellblazer" that's still our longest running series at Vertigo. So when we thought it through and looked back to the early days of Vertigo when the Phantom Stranger would go back and forth and nobody seemed to bat an eye in the process...well, what better character to do that at this moment than Constantine? That's one of the reasons why with the return of Swamp Thing, you see the reintroduction of Constantine to the DC Universe.

Geoff Johns obviously has a heavy hand in how this works itself out creatively, but how did you determine where to roll this out fully? It looks as though the next appearance of these characters in DC books will be in "Brightest Day Aftermath: The Search For Swamp Thing" which is being written by former Vertigo editor Jonathan Vankin. Is that an example of how you wanted to find people to introduce them who'd worked with them and could retain what worked with them at Vertigo while still making them work for the DCU?

Well, one of the things was that we wanted to work with Jonathan Vankin period. We were talking with him about different projects and different ideas, and when this project started to gestate, he seemed like the most natural person to bring to this book and help us with it.

The question most people are going to be asking is simply "How does this work?" With Constantine, there are horror elements, language elements and sexual elements that have been in his stories that I'm sure you don't want dropping into the middle of, say, "Teen Titans." Was there an idea of the pieces of the Vertigo cast you knew would carry over, or is each story done in its own way?

You have to take each story in its own way, but there are two very distinct approaches to how we're bringing Constantine to DCU and Vertigo simultaneously. First, there's not a thing that will change about John Constantine's "Hellblazer" book at Vertigo. That book has a particular voice and a particular style, and it's nothing we want to upset the apple cart on. It's a very successful series for us, and we don't want to do anything that would be detrimental to it. So it will continue with the same flavor, style and tone it's always had. Nothing changes at all. And then when you look at how Constantine fits in the DCU, well...we have a template for that, and it's the Constantine that was in the DCU when he first appeared. He had a voice, a style and a tone, and we're going to use that particular style and voice for the character in the stories we plan to tell with him. We have a template for both versions, and there's quite honestly no reason to merge them. Constantine in the Vertigo universe is in his 60s, and what you have in the DC Universe is a character who is markedly younger. It's something where if you looked at him when he first appeared, he hasn't aged a day. Go figure! [Laughs] You can come up with some story reason for that if you want, but we like to think he's just been waiting for us to bring him back in the DCU.

That brings up a question we'd been talking about over here when Swamp Thing came back: namely, what parts of the characters history will impact them as they appear in the DC Universe moving forward? Aside from "Hellblazer" affecting Constantine's status, Swamp Thing has had a number of Vertigo series over the years. Can we assume that these versions will take their history primarily from what happened up to the DC/Vertigo split?

I would say absolutely. That's not to say that there may not be places within those stories that become inspiration for a story idea now, but like I said before, there's a particular tonality and theme that is unique to Vertigo. That's why we have a separate imprint. It's not because they can curse or there's some sexuality that's not shown in the DC Universe. There's a maturity in the storytelling and a deeper focus and examination of the characters. That works extraordinarily well for that kind of universe. Meanwhile, in the DC Universe we have things that are much more rooted in the action adventure realm, so therefore there's a different style of story that will be taking place with these characters as they'll be used in the DCU that'll be separate from the way they're portrayed in Vertigo. So if a story subject works for the DC Universe, we can use that for story material, but if it doesn't, it can stay -and it's important that it stays - with Vertigo.

The last element that a lot of folks will be wondering is with Constantine now back on the DCU beat, is there any chance we'll see more DC characters appearing in "Hellblazer"?

It's hard to say whether or not there will be DCU characters because it stands so well without them. It doesn't need those types of characters in there. But that's not to say that down the road you might not see Swamp Thing appear back in there. One of the reasons that Constantine is appearing in a book involving Swamp Thing now is that he's created a very integral part of that character's history and storytelling, and I have to think that's reciprocal to how things appear in Vertigo.

Stay tuned to CBR News later this week for more on "Brightest Day Aftermath" with writer Jonathan Vankin!