Appearance and CharacterEdit
Though the true appearance of Ser Arthur Dayne is not confirmed (that said, House Dayne consists of fair skin and hair), he is described by Eddard Stark as having a sad expression. It is possible that he looked like his sister, who was dark-haired, tall and extremely beautiful with violet eyes.
Arthur had the reputation of being the noblest knight since Prince Aemon the Dragonknight, and the most famous Dornishman of his day (excepting his own sister and Prince Oberyn Martell). He was extremely principled and dutiful, following to the highest of his capacities the orders of his royal masters. He was the greatest and closest friend to Prince Rhaegar Targaryen, and a constant companion of his. Arthur's status as one of the noblest knights of his day is cemented by how everyone who even brings up his name cites how great a man he was. During his campaign against the Kingswood Brotherhood, he courageously and courteously allowed his opponent in the Smiling Knight to fetch another sword when his own became too damaged, only to quickly end the duel afterwards.
Arthur Dayne, last but not least, was the greatest knight of his generation, and the deadliest of King Aerys II Targaryen's Kingsguard (which is saying something, since it consists of Barristan the Bold, the fierce Gerold Hightower and the prodigy Jaime Lannister). Wielding a famous greatsword Dawn, Arthur was described as being utterly unstoppable with bare steel, and nobody could stand against him on their best day. Arthur very rarely faced someone who could truly match him, with the rare exceptions being the Smiling Knight and (presumably and debatably) Lord Eddard Stark. Jaime Lannister, who worshiped Arthur in his youth, claims quite correctly that Arthur could easily best all of the current Kingsguard with his left hand 'while taking a piss with the right'.
He was an excellent tourney knight, defeating his friend Prince Rhaegar Targaryen during the tourney of Prince Viserys' birth, and later breaking twelve lances against him at Storm's End but being defeated in Harrenhal.
He was the second son of an unknown Lord Dayne. He spent his youth being taught the art of arms at Starfall, and was eventually deemed worthy of wielding Dawn, the ancestral blade of House Dayne. He was the older brother of Ashara Dayne and Allyria Dayne, and the uncle of Edric Dayne.
At some point he was inducted into the Kingsguard of Aerys II Targaryen, and he would serve under Lord Commander Gerold Hightower.
He knighted Jaime Lannister for his efforts in defeating the dreaded Kingswood Brotherhood, and would personally kill one of their most notorious members, the Smiling Knight. Arthur's defeat of the Knight would be in the midst of a ferocious duel, in which the outlaw's sword became damaged and Arthur allowed him to fetch a new one, before cutting the man down.
He was absent for much of Robert's Rebellion, but would eventually fight Eddard Stark at the Tower of Joy, and would have killed him if not for Howland Reed's intervention. Ser Arthur Dayne perished, and Lord Stark would return Dawn to Starfall out of honour for his opponent. Arthur's body was buried under a cairn made up of rocks from the Tower itself, along with his brothers, as well as Ned's companions.