George R.R. Martin has a warning for fans of HBO's "Game of Thrones": Your favorite character might be on the chopping block, even if they survived in his novels.

“People are going to die who don’t die in the books, so even the book readers will be unhappy," Martin said Saturday at the Writers Guild West Awards. "So everybody better be on their toes. David [Benioff] and D.B. [Weiss, co-creators of the show] are even bloodier than I am.”

Later, the author spoke to Showbiz411 about the future of the series. "Not really certain yet," he said when asked how many more seasons there might be. "This is the fifth season, the sixth season HBO picked up last year. We will have a seventh, eighth or ninth, no one knows. They only renew one or two seasons at a time. After we do Season 6, maybe we’ll get a renewal for seventh and eighth. That all depends. Television is a very changeable medium.”

Martin understands how popular the show is now, but also that the medium can be fickle. Meanwhile, he's going to focus on the remaining books in the series.

“Yeah, it’s the hottest show on TV now, but will it be the hottest show on TV two years from now? Hot shows come and go and television changes, and I’ve lived through that before," he said. "I certainly hope that we get to tell the entire story. Because whatever happens with the show I’m going to finish the books, it will be seven books. But each of these books are 1,500 pages long and they each have enough material in them for several seasons. I have two more books, the one I’m writing right now, The Winds of Winter, and after that the last book, The Dream of Spring, so those will be the two final books. But we’re talking 3,000 pages of material. How many seasons that translates to? That’s up to D.B. And David.”

Game of Thrones Season 5 debuts April 12 on HBO.