Arthur
King of the Britons, Arthur is beloved by his subjects and allies. The son of the deceased Uter (Uther Pendragon), he is presented as being a wise and fair ruler who embodies all the kingly, lordly, and knightly virtues. He has prowess in battle, singlehandedly defeating a giant. He is also an effortless leader. However he is not immune to the twists and turns of fate.
Waynor or Wenour (Guinevere)
Arthur's wife does not speak and is not shown or described in the poem. She is someone that Arthur and the others mention. In Arthur's absence, she forms an alliance with, and marries, Arthur's illegitimate son Mordred who is also the son of Arthur's sister.
Waynor appears only briefly in Arthur's leave-taking scene, where she privately weeps and bewails the war which is separating them. Arthur attempts to cheer her up by saying that he's leaving Mordred to keep her company and to take charge of the kingdom in his absence. From this point forward, Waynor does not appear directly in the story.
Launcelot
King Arthur's closest friend and companion, Launcelot is presented as a brave and noble knight. (His relationship with Guinevere is not discussed in this poem, which omits many parts of Arthurian legend.)
The Emperour
The "Emperour" or Emperor of Rome begins the conflict by sending "Senators" to England to demand tribute and fealty from Arthur. In retaliation, Arthur invades the European mainland. In many respects this character is a foil for Arthur. Whereas Arthur has the ready support of other allies including the "kings" of Scotland and Wales, the Emperor must hire mercenaries, witches, and warlocks. Arthur is presented as the "better" king, however the reasons for his perceived superiority are not explicitly stated. It is suggested that Arthur has divine favor and is preferred by God.
Mordred
Mordred is the son of Arthur's sister (the circumstances of his conception are not explicitly stated in the poem, but conventional Arthurian legends suggest that Mordred is also Arthur's illegitimate son). He is a younger knight, and Arthur leaves him to rule in his absence. He stages a coup, sets himself up as King, and marries Waynor.
Gawain
The grey-eyed knight is one of four sons of King Lot of Orkney, and a loyal supporter of Arthur. He serves as an army officer of sorts and commands other knights.
Fortune
Arthur has prophetic dreams during his European campaign, and in one of them a woman appears with the Wheel of Fortune. She embodies fate or luck, and is not a human character so much as an incarnation of a principle or concept such as some of the virtue or vice characters in "Piers Plowman". She informs Arthur that he's had a pretty good run, but that it is time for his prominence to end along with his reign and his life.
