“Game of Thrones” at this point, deviated majorly from George R.R. Martin’s ASOIAF novels as the show has overtaken the events in the books. The breach of the wall at Eastwatch in the final episode of GoT this season is one major example.

Currently, the Wall still stands and is fully intact in the books. Though it’s fall is widely expected by readers to happen maybe in GRR Martin’s 6th novel of the ASOIAF series, “The Winds Of Winter,” such collapse will not be in the cold hands of the Night King riding Daenery’s reanimated dragon spewing blue flame on the massive chunk of the Wall.

Many followers of the GoT TV series may not be aware that in the books, the one who will likely bring about the Wall’s eventual downfall is the character billed as more malevolent and heartless than Ramsay Bolton—Euron Greyjoy.

It unlikely in the book that a dragon will be the means to bring the wall down. There is a legendary piece of instrument, however, which can do this - the Horn of Joramun.

The Horn of Joramun

The Horn of Joramun also known as the Horn of Winter was mentioned in the ASOIAF novels “A Clash of Kings” and “A Storm of Swords.” It was named after Joramun, who was once the King-Beyond-The-Wall.

It was said that he used the horn to wake the giants from the Earth. According to the lore of the Free Folk, it is an instrument with magical properties that can cause the wall to fall if blown.

Whether the Horn of Joramun really existed or was destroyed is still unclear. Mance Rayder showed Jon Snow a horn believed to be the Horn of Winter but this, later on, was destroyed by Melisandre in the novel “A Dance with Dragons.”

However, Tormund afterward told Jon that Mance Rayder never found the Horn of Winter and the one burned by the Red Priestess was not the legendary horn.

Jon Snow found the horn

In the novel “A Clash of Kings,” Jon Snow found an old warhorn in the Fist of the First Men along with some dragonglass.

This scene actually appeared in season 2 of "Game of Thrones," though it was Sam who found the dragonglass and a horn.

Jon gave the horn to Sam who still possesses it in the books. Sam, on his way to Oldtown along with Gilly and Maester Aemon, has to give almost all that they owned to pay their passage to Oldtown. It is notable, however, that it was specifically mentioned that the horn was among those left of Sam’s possessions.

Oldtown facing an invasion by Euron

In “A Feast of Crow” Oldtown is facing the threat of invasion from Euron Greyjoy. Though what happens next is still to be told in the coming books, the possibility is there that Euron will somehow get hold of the old horn from Sam and could, later on, discover what it truly is.

If GRR Martin in his next ASOIAF novels reveals that the old war horn is the legendary Horn of Joramun and that Euron Greyjoy was able to get hold of it through Sam, then the King of the Iron Islands may well be the one to bring the wall down.