Game Of Thrones Season 6: 8 Ways Battle Of The Bastards Will Be Different In The Books

On the show, Mance Rayder is definitely dead. There's been nothing since his death to suggest that it was a ruse, and even if there had, it's been far too long for a return to make any sort of sense.

In the books, however, Mance Rayder is not only alive (thanks to some glamour magic from Melisandre), but he's at Winterfell, under the guise of the singer Abel.

Mance/Abel is responsible for killing a number of foes within Winterfell, as he and his six spearwives move throughout the castle murdering the Bolton forces. Later, as part of the pink letter that Ramsay (or at least, allegedly Ramsay) send to Jon, it's stated that Mance is "in a cage for all the north to see, proof of your lies. The cage is cold, but I have made him a warm cloak from the skins of the six whores who came with him to Winterfell."

This is the letter that motivates Jon to move on Winterfell, and leads to the mutiny at Castle Black and his death. However, various theories suggest it's not actually from Ramsay, but either Stannis, to force Jon to march on Winterfell, Mance, to try and rally support of Jon and the wildlings, or Lord Wyman Manderly, who is actively planning on betraying the Boltons anyway.

Regardless of who did write the letter, if the Battle of the Bastards is to happen, then Mance Rayder seems likely to be involved, either as the writer or part of the motivation for the resurrected Jon marching on Winterfell. It would mean certain elements staying the same as the show - Stannis' defeat, Jon's swift(ish) return - but alter his reasoning, and in turn likely change how Jon approaches the battle - he dashes forward alone to save Rickon, but that ploy isn't going to work with Mance.