Gaius, the court physician who takes Merlin in when the young warlock arrives in Camelot, is a fairly stoic character from the beginning and provides the father-figure that Merlin does not have. He has the caution that Merlin lacks and can come across as unfeeling in his attempts to stop the young man from rushing headlong into good-intentioned scrapes, but the screenwriters did not make him an idiot. In several instances where Merlin's plan of action is at odds with Gaius', Gaius is eventually shown to be the wiser one as Merlin, ignoring advice and blundering on, creates more trouble rather than fixing the problem.
"You have taught me so much: taught me who I am, taught me the purpose for my skills, taught me that magic should only be used for great deeds. But most of all, you have always taught me to do what is right." (Le Morte D'Arthur, Season 1 - Merlin to Gaius.)Uther, King of Camelot, is one of the most interesting character studies of all the Merlin cast. He is not an out-and-out villain, but he certainly is not a hero, nor even a good guy; he has suffered at the hands of sorcery (yet has also benefited by it) and lives in fear of all kinds of magic, swearing that Camelot will never fall to sorcery while he is king. His fear controls him, and any mention of sorcery drives all reason right out of his head. His acts are often condemnable and either fear- or self-driven, and he shows neither mercy nor understanding.
At the same time, he is not written (or played) as a wholly black-hearted ogre with no background or emotions. While I don't believe that a person's past in any way condones evil in their present actions, or that men and women are "basically good," yet in a story it is often more believable to give an antagonist an understandable history, rather than to say, "He's simply evil. So there." The writers of Merlin pulled this off with Uther by revealing some of his past encounters with sorcery and showing both the good and the evil that came of it.
As for Uther's emotions, several episodes reveal his deep love for his son, Arthur, and for his ward, Morgana, and his willingness to do anything to protect them. While these feelings also lead to wrong choices quite often, they have the effect of softening his character somewhat so that viewers can have some sympathy for him, while still wanting Arthur to take the throne.
"...He's a broken man consumed by fear. His hatred of magic has driven goodness from his heart." (The Nightmare Begins, Season 2 - Aglain to Morgana.)Nimueh, the arch-nemesis of Season 1, is the opposite of Uther and yet also very similar. She is a powerful sorceress whose mission is revenge for the lives of her fellow sorcerers whom Uther has killed, so she represents all that the king has sworn to destroy. At the same time, though, her past and Uther's are linked, and the writers employed the same tactic they used for Uther in giving Nimueh a history to make her an understandable - though not a sympathetic - evil. She is not thrown into the role of villain with a mere, "I hate everyone just because." She has purpose, and that makes her even more evil - and thus a better antagonist.
"I have watched so many people I love die at your hands, Uther Pendragon. Now it is your turn." (Excalibur, Season 1 - Nimueh to Uther.)The Great Dragon whom Uther imprisoned years ago beneath the castle is the narrator of the series and something of an enigma. He is the one who shows Merlin that his purpose is to protect Arthur at all costs and to get him to the throne of Camelot, but the Dragon's motives become increasingly suspect as the first season progresses. The question of whether or not he can be trusted adds a further element of suspense to the storyline, as he is often the only character strong enough or wise enough to help Merlin. It also makes him three-dimensional and allows for a contrast between himself and Merlin, between the Dragon's self-serving mindset and Merlin's self-sacrificing spirit. Had the screenwriters made the Dragon a purely good character, it would have had the double effect of making him flat and taking out a large portion of Merlin's moral struggles.
"Your destiny is to protect the young Pendragon until he claims his crown and, when he does, magic can be returned to the realm. Only then will I be free." (Le Morte d'Arthur, Season 1 - The Great Dragon to Merlin.)Morgana, niece and ward of Uther Pendragon, is another difficult character whose true colors have yet to be revealed. Throughout the episodes she has had dreams in which she has glimpsed the future, making Gaius, who prescribes medicine for her nightmares, wonder whether she may have the same sort of magic that Merlin does. Though she is usually a sweet and goodhearted young woman, she has a darker side - fierce loves and hates, a quick and passionate temper, and a lack of guidance. She is unpredictable and has the capacity to turn into sorceress like Nimueh, and as her character and powers are slowly revealed, they give more force to the question of her future.
"I am never going back. These are my people. They are like me. I don't feel so alone here." (The Nightmare Begins, Season 2 - Morgana to Merlin.)Guinevere, or Gwen, is Morgana's maidservant and friend and represents her polar opposite. Where Morgana is fiery, Gwen is subdued; where Morgana is sarcastic, Gwen is sweet; where Morgana flies into a passion at the hint of injustice, Gwen accepts her lot with resignation. She is loving and full of blessings for almost everyone; but like Morgana, Gwen has convictions and frequently voices them, though she generally regrets it afterward.
An interesting point that is brought out by the second season is that, though Morgana is the king's ward and the prettier of the two women, still it is Gwen's sweetness that attracts the men and makes her the subject of the age-old question in fiction, "Who is she going to marry?" Her natural openness and affection has torn her between two men, and I have yet to find out how the screenwriters will resolve it.
"Gwen is the most kind, loyal person you would ever meet and she's been more than a friend to all of us." (Lancelot and Guinevere, Season 2 - Morgana to Arthur.)Lancelot, probably the third most well-known character of the Legend of King Arthur, is portrayed in the BBC series as a great swordsman, but not a nobleman and thus not eligible to serve as one of the Knights of Camelot. Unlike in most of the King Arthur tales, he is a humble man whose one goal is to serve the king of Camelot, and whose character is far nobler than any real nobleman's. He has actually only appeared in two episodes so far (once in Season 1 and then again in Season 2), but the screenwriters have established him so well in those that he is not "out of sight, out of mind"; he is a critical player, but exactly what part he will eventually play remains to be seen.
"For all my words, for all that I believed, I've come to nothing." (Lancelot and Guinevere, Season 2 - Lancelot to Guinevere.)And this is the part where you wonder where Arthur and Merlin himself have gotten to in this list. However, they deserve a compare-and-contrast post of their own, as Dr. Watson did, so their character studies will come later.