Lancelot: Lancelot was a close friend of Merlin and later is a knight of Camelot. he was Gwen's first love and was one of the few characters that knew about Merlin's magic, he decided to kept it as a secret. he had a strong sense of what is right was not right. for him Merlin is the bravest man that Arthur have and he think that Arthur let Merlin to join the knights. he will do everything for Gwen even die for her. He lost his life sacrificing his live instead of Arthur's life. Arthur decided to make him a honorable funeral. Lancelot later returns by Morgana's magic to cancel Gwen and Arthur's wedding, making Gwen to fall for Lancelot for this Gwen is exiled from Camelot by King Arthur and Lancelot returned to the world of spirits by Morgana's order.
Morgause: Morgause is a powerful wizard who is the older and half sister of Morgana. Her Magic is equal or more or less equal to Merlin's magic. she wished for her sister the best and to rise as the new queen of Camelot instead of Prince Arthur, for that reason she will take away any bother out of he way. she is aware that she won't become queen she knows that her sister is the one that will rise, she loves Morgana and she have many good influences that can help her in her evil plans. With Morgana at her side she is invencible. she decided to die as a sacrifice for the sake of her sister.
Gwaine: Gwaine is a close friend of Merlin later of help him and Arthur in tavern. he is good at fights. he has a crush on Gwen but just for a short moment. Gwaine is the son of a Knight so Merlin cheer him telling him to join the Knights of Camelot but as Merlin he dislike King Uther who exiled him from Camelot. he then help Merlin and Arthur many times, When Arthur rises as the new King, Gwaine decides to try to be a Knight of Camelot. During the missions Merlin and Gwaine passes many times together since they are close friends.
Elyan: Elyan is the brother of Gwen, he was kidnapped by Morgause and Cedric to thretaned Gwen. he later is rescue by Prince Arthur, Gwen, Merlin and Morgana. he is good a fighting, he loves his sister Gwen but they didn't much interact for a long time when he decided to run away from home with any way of contact. When his sister Gwen and the others went to rescue him he show how good he is at fights for that reason prince Arthur congratulates him at the time , saying that practice makes you better, Then when Arthur rises as the new king, Elyan is a knight of Camelot.
Leon: Leon is a knight of Camelot who is loyal to Prince Arthur and then to King Arthur. Leon is saracastic and always teases Merlin. he knows that Arthur make Merlin's life a frustation. Leon as the other others is part of the round table lead by King Arthur. He is loyal not only to Arthur, as a knight of Camelot he is able to give his life for the sake of Camelot, he is loyal to Gwen and to Merlin. He is on good terms with every member of the round table/
Percival: Percival is a Knight of Camelot, his closest friend id Leon. Percival is loyal to Prince Arthur and then to King Arthur. as well he is loyal to Morgana until to her betrayal, Gwen and Merlin. Percival was a friend of Lancelot until his death as he was he first friend. Percival is a member of the round table. he is a quiet man and he is very brave and strong. As the others Knights he would sacrifice his life for Camelot or for King Arthur.