With just 13 more episodes left of Game of Thrones, spread throughout two shortened seasons, many fans were excited to learn in May that HBO and author George R.R. Martin are developing four new Game of Thrones spin-offs. The author himself confirmed just a few days later that they are all prequels, set before the events of the flagship series, while adding that there is now a fifth show in the works. Still, the odds of all these shows making it to air are quite slim, according to an HBO executive.

There are only a few concrete details we do know about the spin-offs. It has been confirmed that writers Max Borenstein (Kong: Skull Island), Jane Goldman (Kingsman: The Golden Circle), Brian Helgeland (L.A. Confidential) and Carly Wray (Mad Man) have been brought on to write these shows, although it hasn't been confirmed if a fifth writer has come aboard for the latest. The author also confirmed that none of these prequel shows will be based on his Dunk & Egg stories, a series of novellas that are set 100 years before the events of the books and TV series, following the adventures of the two title characters. The Hollywood Reporter caught up with HBO programming president Casey Bloys, who thinks it would be unlikely that more than one of these shows eventually makes it to the HBO airwaves. Here's what he had to say about what might happen, if three or four of these shows turn out to be great.

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"You know the odds in development. I think that is probably unlikely. I was at Touchstone during Who Wants to Be a Millionaire. They had a hit show and they aired four in a week. This show is very special. I'm not looking to have as many as possible. My sense right now is we would be very lucky if one of the four rises to the level that we have set. Now, theoretically, what if they're all great? That's a high-class problem that I'll solve when it comes to that. But knowing what we know about the development process, that's why we wanted to increase our odds. But I do not see a scenario where we have more than one. But again, high-class problem."

As for the 5th Game of Thrones prequel that George R.R. Martin announced on his blog in May, the writer stated at the time that HBO would announce who this writer is, "once his deal has closed." It seems that hasn't happened yet, since, when asked about the fifth writer, Casey Bloys would only state that, "I have a deal for four spinoffs right now with four writers." Regardless, if there is one show that does make it on the air, it would mark the first time HBO will revisit one of its original series for the small screen, although there is also a Deadwood TV movie in development. When asked why they're developing so many shows at once set in this same universe, Casey Bloys revealed that they wanted to 'increase the odds' of finding a show that works, while clarifying that these spin-offs won't air immediately after the final season.

"This franchise is really rich and very exciting. It is going to be really, really hard for anybody to match the level that this show has set in terms of quality and filmmaking. So the idea was, if we're going to try it, let's take a couple of shots and see. My hope is at least one lives up to the level of quality Benioff and Weiss have set. But again, it's also very early in the process. I haven't even seen an outline for them. The priority here is obviously season seven and then season eight. You're not going to see a situation where we're launching a prequel on the back of the final season. The final season is going to be its own event. It's going to be a big deal for us and the fans. I'm not interested in using it to launch any other show. We mentioned the spin-offs because obviously there's a lot of interest in them, but it's a very embryonic process, and you know how development goes, it can be a long process. We confirmed their existence because there was a lot of interest, but it's not something that we are fast-tracking to get done to air immediately after the final season. I'm guessing fans will need some time to decompress from how amazing the final season is."

Casey Bloys was also asked about a statement he made just a month ago, when he hinted that Game of Thrones Season 8 may not be ready to air until 2019, adding that "he can't really speculate on that." He did state that series creators/showrunners David Benioff and D.B. Weiss are currently writing the season and putting it all together, so the production schedule will dictate the release schedule. Regardless of the final season or these spin-offs, fans will be able to return to Westeros in just a few short days, when Game of Thrones Season 7 debuts Sunday, July 16 at 9 PM ET on HBO.