Stannis Baratheon (Stephen Dillane) is reportedly confirmed dead and may only appear in season 6 as a corpse. The Watchers on the Wall's Sue Miller posted evidence for this via Twitter, where she reveals a passage from the recently released companion book for the show, "Game of Thrones: The Noble Houses of Westeros."
Stannis was last seen in "Game of Thrones" season 5, where he and his army lost their siege against Ramsay Bolton (Iwan Rheon) at Winterfell. After escaping the battlefield, he was found by Brienne (Gwendoline Christie), who apparently slashed at him. It was not revealed if she did indeed strike him down.
That mystery may now be solved. According to the book's passage, Stannis was indeed killed by Brienne of Tarth right where she found him, in the woods outside Winterfell.
According to Brienne, her motivation to kill Stannis stems from his act of using magic to kill his brother Renly (Gethin Anthony) back in season 2. At the time, Brienne served Renly as a part of his "Rainbow Guard."
HBO teased this detail before with the release of the "Beautiful Death" art for Stannis Baratheon right after the episode aired. It is important to note that these posts are solely dedicated to characters confirmed dead on the show.
Jon Snow (Kit Harrington) has not been given a "Beautiful Death" post as of yet, which is why he is speculated to live or at least be revived while Stannis is mostly believed to be dead.
However, while the evidence points to Stannis being dead on the show, the character has been confirmed by author George R.R. Martin to be alive and well in the books. He confirmed this on his official blog as a response to a question as to whether Stannis had survived the siege on Winterfell or not.
"Game of Thrones" season 6 will premiere in early 2016.
