The journey of Bran Stark has gone on from the first season of "Game of Thrones" where he was pushed off a tower window by Jamie Lannister. He has since been paralyzed from the waist down but has still managed many different adventures through the help of his loyal servant Hodor, the Stark's wildling hostage Osha, his direwolf Summer and his friends Jojen and Meera Reed.
After their escape from the clutches of Theon Greyjoy and the fall of Winterfell to Ramsay Snow, Bran has been on the run with his companions and in the course of their travels which was first intended to take them to Castle Black to rejoin his brother Jon Snow, Bran has been experiencing visions in which he sees a three-eyed-raven. The raven has then led him to go North of the Wall which he was able to do through a tunnel with the help of Sam Tarly.
Exactly what or who is this three-eyed-raven?
The three-eyed-raven is a character which is also believed to be the last greenseer in Westeros. A greenseeer is part of an ancient group of people called the children of the forest who had magical abilities that included power over nature and prophetic visions.
Greenseers were wargs and skinchangers as well, an ability that Bran and possibly other members of the Stark family possess as seen through his possession of Summer and Hodor. Greenseers are believed to be the ones who were responsible for carving the faces into weirwood trees. Greenseers are able to see through the faces of their weirwoods, influencing animal and plant life.
One in a thousand men is born a skinchanger and one skinchanger in a thousand is born a greenseer.
The last greenseer, Brynden Rivers
The last greenseer and the man coming to Bran as the three-eyed-raven was known as Brynden Rivers. Rivers was the bastard son of King Aegon IV Targaryen and his sixth mistress Lady Melissa Blackwood. Rivers became Hand of the King, serving throughout the reign of his nephew King Aerys I Targaryen.
Brynden is an albino and had milk white skin, long white hair, and red eyes. On the right side of his face he had a red wine stain birthmark that extended from his throat up to his right cheek from which he earned his name "Bloodraven."
As "Lord Bloodraven," Brynden was rumoured to be a sinister sorcerer who effectively ruled the kingdom with spies and spells.
During the reign of Maekar I, who still disliked him, Bloodraven was kept imprisoned in the Red Keep's black cells until the year of King Aegon V Targaryen ascended to the throne. He was then sent to the Wall as part of the "honor guard" of prisoners that accompanied Aegon's brother Maester Aemon. Eventually he rose to Lord Commander of the Night's Watch.
Bran finally meets the three-eyed raven
Bran discovers Brynden North of the Wall where his near skeletal body is lying in a cave with weirwood roots growing through him. He then trains Bran in the arts of being a skinchanger and a greenseer. It then remains to be seen what the two of them will be able to achieve in the battle against athe White Walkers and in the great conflicts happening all over Westeros.