Ian McShane is an older British gentleman with a fascinating, craggy face who has the ability to grow killer facial hair. So yeah, it was actually kinda’ inevitable that he would join Game of Thrones at some point. Jokes aside, it’s genuinely exciting to see Al Swearengen himself return to HBO. As one of the few members of the Deadwood ensemble who can slide right into Westeros, we can’t help but approve. Like The Wire, our very souls get tingly when we see Deadwood cast members pop up in other shows. Game of Thrones is now a little more perfect.

We don’t know who McShane is playing in Game of Thrones and the original announcement seemed to indicate that his role may remain a secret for at least a little while. We do know that his screen time will be limited but that “his character is of key importance.” With only those clues to go on, we can narrow this down. There are five characters that we think he can play in Game of Thrones season six.

From here on out, we assume that you’ve caught up on Game of Thrones. We will also delve into minor book spoilers and discuss a few popular fan theories, but the big stuff will have a spoiler warning. Still, if you’re very sensitive about this kind of thing, feel free to turn back now.

Ser Arthur Dayne

Since season five opened the door to flashbacks in Game of Thrones, it’s inevitable that we are finally going to witness the mysterious events that took place at the Tower of Joy. And if we’re going there, we are surely going to meet Ser Arthur Dayne, a member of The Mad King’s Kingsguard and the most noble, fearless, and deadly knight in the seven kingdoms.

In one of the books’ most tantalizing moments, a young Eddard Stark arrives at the Tower of Joy in Dorne, where Rhaegar Targaryen has hidden Lyanna Stark (whose abduction led to Robert’s Rebellion in the first place). Standing guard are three knights, Arthur Dayne among them. Although Eddard and his six companions outnumber the three knights, only the young Lord of Winterfell and one of his allies survive the encounter. What they discover when they find a dying Lyanna inside the tower is...well, that would involve taking a deep dive into A Song of Ice and Fire’s greatest conspiracy theory.

Arthur Dayne is generally depicted in fan art as being young-ish and handsome, but the weary and wise McShane is more than capable of playing Westeros’ finest warrior. He may only appear in a single flashback, but Dayne leaves a lasting impression on enemies and allies alike, who frequently mention him and his adventures in every book in the series. Heck, this is the guy who knighted Jaime Lannister. If Game of Thrones wants to establish this guy as a Big Deal the moment we see him, casting McShane would be great cinematic shorthand.

Lord Randyll Tarly

When we first met Samwell Tarly, we learned that he was sent to The Wall by his cruel father, who couldn’t stand the thought of his cowardly elder son becoming the next Lord of Horn Hill. Although he hasn’t been a major player in the novels (yet), it’s no secret that Lord Randyll Tarly will be showing up in season six.

As one of House Tyrell’s most loyal bannermen, Randyll Tarly has actually been active behind the scenes of major events throughout the series. He fought for the Crown during Robert’s Rebellion, defeating Robert Baratheon’s forces in battle. He was present at Storm’s End when Renly was assassinated by Stannis. He even commanded forces at the Battle of the Blackwater. He’s one of Westeros’ most seasoned warriors and a highly effecive military commander. And he’s also a total dick.

It’s easy to imagine McShane playing an icy father who would have no problem giving his own flesh and blood a choice between The Wall and an “accident” that would result in his death. He can play callous in his sleep. It’s kind of his thing. Most importantly, McShane’s mystery character is supposedly vital to the show and Randyll Tarly is one of the few men in the seven kingdoms with a Valyrian Steel sword. You know, one of the the only weapons capable of killing a White Walker.

Euron Greyjoy

Everyone on the internet has already fan-cast Mads Mikkelsen as Balon Greyjoy’s younger brother, but we can easily see McShane sliding right into this role. Theon and Yara’s mysterious, long-absent uncle is one helluva character, a violent and terrifying pirate who makes the rest of his family look downright cuddly in comparison.

The captain of The Silence, a ship whose crew have had their tongues forcibly removed, Euron has spent years exploring the known and unknown world. He has big plans for House Greyjoy...plans that involve reigniting the war they’ve supposedly lost. And unlike his family members, he’s been around the world and back and has learned all kinds of weird, creepy and unknowable things. This is the kind of guy who keeps a crew of warlocks hostage so they can coach him in magic. This is the kind of guy who actually has a contingency plan for Dragons.

Euron is a first class manipulator and schemer, the smartest and most vicious guy in any room. Although casting McShane as a supernatural pirate may give us some awful Pirates of the Caribbean: On Stranger Tides flashbacks, we’d never say no to watching him play an outright bastard like this. Euron could be the break-out character of season six and casting a familiar face in the part could be a wise movie.

The Elder Brother

In their travels across Westeros, Brienne of Tarth and Podrick Payne happen across The Quiet Isle, a community of penitent men who have taken a vow of silence and live to serve the Seven. Their leader, and the only man who speaks, is known as the Elder Brother. A former knight who gave his life to his faith and became a healer, he spends his days helping others atone for past sins and assisting the sick and wounded. In conversation with  our heroes, he reveals that he found the dead body of Sandor “The Hound” Clegane and buried him, providing closure for one of the series’ most popular characters.

And he may be a much bigger deal than he lets on. Speculation and possible spoilers in the next paragraph!

A popular fan theory (with juuust enough evidence to back it up) suggests that the Hound is actually alive and living on the Quiet Isle. After all, the men have all taken a vow of silence and they all wear hoods that obscure their faces. And Brienne does spy a very tall gravedigger with a pronounced limp. If this theory is true and Sandor Clegane is alive, casting a noteworthy actor like McShane as the man keeping him hidden and guiding him to redemption would make a lot of sense. If not, expect this character be played be someone else (if he shows up at all).

Lord Howland Reed

He has only been mentioned in passing on the show, but Howland Reed may be one of the most important characters in all of Game of Thrones. The only other survivor of the skirmish at the Tower of Joy, the Lord of Greywater Watch (and the father to Jojen and Meera Reed) was present when Arthur Dayne and his fellow knights were struck down. . Now that Eddard is dead, he is the only living person who can explain exactly what went down after they found the dying Lyanna Stark.

If you don’t want to delve into spoilers and fan theories, stop here. Just know that Howland Reed is a big deal and that the books have gleefully kept him far away and out of view. When we finally meet him, he’s going to have to answer some pretty big questions.

Although Jon Snow certainly looked dead at the end of season five, he won’t be dead for long. Because he’s coming back. Somehow. Probably by magic. And he’s coming back because Howland Reed knows the truth about him. When he climbed the Tower of Joy with Eddard, they found Lyanna giving birth to Rhaegar Targaryen’s son. And before she died, she made her brother swear to keep him secret and safe. And thus, Jon Snow, a secret Targaryen with the blood of the North and the blood of the dragon running through his veins, was born.

This is the most popular theory in all of A Song of Ice and Fire and it makes too much sense to not be true. However, Howland Reed is literally the only character in all of Westeros who knows this. If it’s true, we have to meet him sooner or later. When we do meet him, wouldn’t it be a pleasant surprise to see that he’s played by Ian McShane?