Sir Gwaine ~ "You know what I like about Merlin? He never expects any praise. All these things he does just for the good of doing them".

Sir Gwaine was portrayed as a fun-loving, laid-back and highly loyal character, wholly dedicated to doing what he believes to be right. His introduction showed him to be a rather reckless and carefree man who thought about little more than ale and women, though Arthur and Merlin soon learned that he respected honour and loyalty above all else. Gwaine displayed his selflessness and courage by saving Arthur's life twice, despite having been banished by Uther Pendragon. Gwaine also proved to have a humble nature since he refused to reveal his noble heritage, telling Merlin his lifestyle had taught him that titles were not important.

Gwaine values respect earned through actions over prestige inherited through a title, and also prefers the freedom of the vagabond lifestyle. Gwaine generally dislikes people of noble blood, seeing them as corrupt, selfish and power-hungry. However he proved an astute judge of character, seeing the fairness and honesty of Arthur, even referring to him as a friend at one point. He showed his defiant streak and refusal to bow to authority by criticising Uther Pendragon in front of Arthur, saying that he might one day be able to return to Camelot when it was ruled by a half decent king. Gwaine had a very trusting nature, largely seeing the best in people and forming a fast friendship with Merlin. Gwaine also had a good sense of humour, frequently seen to be the orchestrator of jokes among the knights, talks constantly on quests, was well known for his mindless and endless chatter and is ever-cheerful and optimistic.

Gwaine was shown to have a fairly extensive knowledge of magic, even though he couldn't use it himself. This was shown in his recognizing and telling Merlin the creatures in the distance were Wyvern. He seemed to be quite accepting of magic, unlike most of Camelot's Knights, and although he threatened Dragoon the Great this was only because the other Knights had informed him about Dragoon's supposed crimes. Gwaine was grateful to the Euchdag because it had healed him and made friends with it telling Arthur he owed it his life.