Who is Ian McShane playing in Game of Thrones when it returns this spring for Season 6? Not even the most hardcore fans have a clue. But the legendary actor, perhaps best known for playing Al Swearengen on HBO's Deadwood, is offering a major clue. And it sounds like his role is very important. Though, his presence on the fantasy series may be short lived. Be warned, there will be SPOILERS ahead!

With the Game of Thrones Season 5 finale, the acclaimed drama series reached an interesting place. It finally caught up with George R.R. Martin's A Song of Ice and Fire novels. This means that fans of both the books and TV show are in the same boat. They have no clue what is coming next. There are quite a few characters whose fates remain unknown. And there is room for much speculation. Add to that, the fact that various plot points from published books four and five have never been expounded upon. Anything is up for grabs.

The only concrete evidence of what is happening in these new episodes comes courtesy of a few new casting additions. Though, there are quite a few new actors coming aboard who's characters have yet to be revealed. We know that James Faulkner is playing Sam's father Randyll Tarly. But who will Richard E. Grant and Essie Davis be playing? Joe Naufahu has also been set in a mysterious new role. But perhaps most intriguing is the presence of Ian McShane. We have no clue what he's about to bestow upon the viewing audience. But now, courtesy of an interview with PopGoestheNews.com, we are offered a major clue. The actor gives this insight into his mysterious presence on the show.

"I'll give you one hint. I am responsible for bringing somebody back that you think you're never going to see again. I'll leave it at that."

Most speculate that Ian McShane's character has nothing to do with bringing Jon Snow back from the brink of death, even though fans believe Snow will return in some fashion. It is Lady Stoneheart who some are sighting as a likely tie-in for Ian McShane' character. She has been rumored to appear even before Catelyn Stark was taken out in a tsunami of blood. The producers have denied that Lady Stoneheart will ever have a presence on the show. But the theory is not without merit. In the novels, she leads the Brotherhood Without Banners.

More likely, though, is that Ian McShane will participate in the reemergence of The Hound, Sandor Clegane, played by Rory McCann. No one thought they'd ever see him again. When we last saw The Hound, he was on the verge of death, suffering wounds at the hands of Brienne of Tarth after their infamous duel. Though he begged Arya to kill him, The Hound was left to bleed out in the Riverlands. Perhaps he survived that awful fate? His demise was not witnessed on screen, so it remains a possibility.

Stannis Baratheon's somewhat ambiguous death last season has since been confirmed as the real deal. Though, thus far, no one involved with the series has said the same for Clegane. The fourth novel even hints that The Hound had been brought back to good health by the Brothers of the Quiet Isle, a subset of the Faith of the Seven. In that book, Brienne and Podrick meet up with Septon Meribald, a character many believe will be introduced in Game of Thrones Season 6. They are taken to Quiet Isle to meet the Elder Brother. He informs them of The Hound's death, but his description of events is vague. He explains that even he, himself, has died. And he was reborn on Quiet Isle. Many readers took this to mean that Sandor had lost his more violent side, and was reborn as a gentlemen.

This has led some to assume that Ian McShane may actually be playing Septon Meribald, or possibly even the Elder Brother. There are even fans who think that both characters will be merged into one to better streamline the expansive narrative set up in the show. When the actor was cast, it was said that he was of 'key importance' but that he had 'a relatively small amount of screen time.' This falls in line with someone who might actually be The Hound's redeemer. Of course, this is all speculation at this point, though. But if this is all true, why is The Hound back, and what will his purpose be in Game of Thrones Season 6? Do you think this is who Ian McShane is playing? Or do you have a theory of your own? Let us know in the comments below.