George R. R. Martin, whose novels became the basis for HBO's "Game of Thrones," recently shared a list of his favorite characters that have so far not appeared on the popular show. Martin is currently working on “Winds of Winter,” the next installment in his series of novels. He recently spoke with Entertainment Weekly about the TV adaptation of his work.[Spoiler alert]

Perhaps one of the most popular characters and possibly one of the most important missing characters from the show who has a major impact on the story line is Lady Stoneheart. The character is the resurrection of the dead Catelyn Stark, played by Michelle Fairley in the TV series.

Comparing the character to that of Gandalf of “The Lord of the Rings” books, Martin explained how he was inspired by the death of Gandalf because it made him realize that any character can die in a book series. However, Gandalf later returned and remained very much the same person as before.

But Lady Stoneheart was different and death had changed her. Martin pointed out that Lady Stoneheart has an important role in the books and the fans of the book series will find out more about the character and her impact on the whole storyline in the forthcoming “Winds of Winter.”

Other characters that are the author’s favorites from the book series are Strong Belwas, Jeyne Poole and the two elder brothers of Loras Tyrell. The brothers apparently also figure prominently in the last two books of the series.

Martin did however admit that there are “thousands” of characters in his book series and it may be difficult for the David Benioff and Dan Weiss, the creators of the show, to feature all the characters. The creators of the show are working “24/7, 12 months a year,” Martin said.

There has still been no official announcement about when “Winds of Winter” will be released. Speaking to Entertainment Weekly, the author revealed that he is turning down interviews and personal appearances to focus on the book and “get this done.” Martin will not be writing any episodes for the next season of “Game of Thrones,” and according to the report, he is “making every effort” to finish the book.