John Constantine has made his way to Star City, and Arrow and Constantine fans are rejoicing.

But...how did that happen? Following the cancellation of NBC's Constantine last season, it could have been that we didn't see the character -- especially as depicted by fan-favorite Matt Ryan -- again anytime soon. Instead, less than a year later, here he is.

Recently, ComicBook.com's Jim Viscardi had a chance to speak with Mericle about the state of the series -- and ask a couple of questions about tonight's Constantine crossover episode.

I know getting Matt Ryan on board to play Constantine for an episode was something you guys were working to, and were glad to make happen. Is that something we'll see more of? Maybe not necessarily with Constantine, but with other potential characters down the line as they come in for little one-off bits here and there?

We would love to do that. It's always a question of where those characters are in the DC universe. When I say the DC universe, I mean beyond the The Flash/Legends/Arrow universe that we've created here. It's up to DC a lot of the time, and Warner Brothers and what their plans are. It's always a dance of sorts to figure out where those characters are going to be and whether they're available. Absolutely, we were so excited to get Matt Ryan. The episode turned out really well. He's such a breath of fresh air. He brings a completely different vibe and a completely different level of charm and fun to the show. We were very excited about that.

With that sort of success, it's definitely something that we would love to do in future episodes. In addition to the crossovers and having Barry and other characters from The Flash come over, and also from Legends. We'll definitely be looking to do more of that if we can.

What is it about adding a character like Constatine into the mix that got you excited?

What we really liked about how Constantine came into our season was: it was based very much in the world of our characters. It wasn't just, "Hey, let's have Constantine on the show because that would be cool!" It was, "Well, we actually need his particular skill set for this storyline", and he also fits in thematically with the bigger picture stuff that we're doing with Damien Darhk and exploring the seam and the idea of magic and what it means to our universe. It was exciting to have an opportunity to do that.

I think that, more than anything, will drive whether or not he returns to the show, and also any other future DC characters we want to bring in. We always try to keep it grounded and within the world of Arrow, and centered around at least one of our main three characters. Digg, Oliver, Felicity, one of them. This season in particular. It should be tied to one of their story arcs.