HBO

You thought the Game of Thrones universe was complicated? Try figuring out the universe of Game of Thrones sequels, prequels, or, as author George R.R. Martin likes to call them, successor shows. Monday in a post on his Not a Blog website, Martin confirmed that his most recent book, the giant Targaryen family history Fire & Blood Vol. 1, has inspired HBO to start work on a new show.

"(It's) also a prequel," he writes. "Set thousands of years after (writer Jane Goldman's) show in the history of Westeros."

Martin also revealed that of the original five Game of Thrones successor shows HBO was working on, three remain. Goldman's show is the furthest along. Its title still hasn't been revealed, but Martin has referred to it as "The Long Night," while acknowledging that he's "not supposed to" use that title.

Deadline reported last week that the Fire & Blood-based show was in the works. A representative for HBO said the network will not confirm the news, but Martin's post seems to do just that.

The author shared a variety of tidbits, noting that the show has a title, but "it's not the obvious" one, which would seem to indicate it's not called Fire & Blood. It has a script, he said, presumably for the pilot, and a "bible," which is kind of a reference book for the characters, settings and other facts of the show. He confirmed the involvement of Ryan Condal, co-creator of the sci-fi show Colony, and Martin wrote that he "loved working with him."

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And don't get too excited yet. Martin warned HBO has not yet ordered a pilot episode for the show, noting that if that happens, he will be "shouting it from the rooftops."

But he did note that one important class of characters from Game of Thrones will be returning. "I can say that there will be dragons," Martin wrote. "Everyone else has said that, so why not me?"