Arthur and Merlin

On their first meeting, Arthur and Merlin got off on the wrong foot. Merlin, not knowing who he was, stood up for a servant Arthur was bullying, and the two then had a brief tussle. Nonetheless, from early on Arthur acknowledged that Merlin was "an idiot", but a "brave one". To both their chagrin, Uther appointed Merlin as Arthur's manservant as a 'reward', which led to Arthur considering him an incompetent and insolent servant, though they quickly developed a grudging affection for one another. Very soon in their friendship, they were openly willing to risk their lives against the advice and orders of others, even knowingly sacrificing for the other (The Poisoned Chalice). They had also saved each other from peril numerous times, though often Arthur remained unaware of Merlin's secret intervention. They frequently bickered and played tricks on each other, though they rarely truly fell out. Arthur saying "shut up, Merlin" whenever the latter pointed out inconvenient truths or made poor attempts at humour became something of a catchphrase. He also often called Merlin an "idiot" and scolded him for being seemingly thick and clumsy, but at the same time seemed to be aware that there was far more to him beyond his happy-go-lucky personality. Although Arthur frequently teased and abused Merlin, occasionally claiming they could not be friends as he was a servant, the two of them become very close and Arthur was often grateful for Merlin's company, loyalty, help and advice. Princess Mithian also stated that during her stay in Camelot she noticed that Arthur valued Merlin's advice above all others (The Hunter's Heart).

Arthur entrusted Merlin with most of his secret activities and missions, and often required his help (The Gates of Avalon, The Beginning of the End, Le Morte d'Arthur, Lancelot and Guinevere). The rest of Arthur's secrets, particularly his romantic feelings, could easily be deciphered by Merlin, who seemed highly in tune with his true nature and emotions. However, Arthur in turn was predominantly highly unsuccessful in guessing Merlin's intentions, believing him to be in love with Gwen, Morgana and even Lady Catrina as a result of Merlin's many secret investigations and odd behaviour. Merlin was also one of the only people besides Gwen who could, despite the class divide, reprimand Arthur when he was being unfair or arrogant, and tell him truthfully what he was thinking without fear of severe punishment. He had often insulted Arthur, calling him a "prat", "dollophead", and a "clotpole," as well as "supercilious" and "patronising." Arthur in reality trusted and appreciated Merlin, although he had sometimes confessed that he thought that Merlin was hiding something. Arthur refused to believe that Merlin was a sorcerer, reacting with incredulity and doubt whenever he was accused of it, and saved Merlin from the suspicions of Uther several times by making up stories (The Mark of Nimueh, The Witchfinder, Goblin's Gold).

Although Arthur did not always immediately believe Merlin's warnings, he defended and rescued his friend even when he had doubts himself (The Labyrinth of Gedref, Beauty and the Beast). However, though Arthur trusted Merlin, he would still often side with his family members and higher-ranked advisers over him, refusing to believe Merlin informing him of Agravaine's treachery (The Hunter's Heart), and would flat-out tell him to be silent when he pushed too far. Arthur and Merlin, though they would deny it, were close to the extent where Merlin was often one of the few able to reach him when others could not. However, Merlin continued to hide his powers from Arthur, knowing that it was too dangerous to reveal it after the time spent together. Despite Merlin's status as a servant, Arthur displayed great trust in him and appreciated his opinion and wisdom, sometimes even enough to uncharacteristically thank him for it (The Tears of Uther Pendragon, The Changeling, The Coming of Arthur – Part 2). However, Arthur was still well aware of his status as prince and was angry at Merlin when he and Gwaine came to help him on his quest for the Golden Trident, though this anger did not last long and he ended up appreciative of the assistance (The Eye of the Phoenix).

Before the retaking of Camelot, Merlin was able to shake Arthur out of his despair and inspire him to continue, leading to the retaking of Camelot from Morgana. Merlin was offered a place at the Round Table, showing how Arthur valued him on the same level as his most trusted knights, and even commented that he was somehow "wise" on at least two occasions. In spite of this appreciation for Merlin's virtues, however, Arthur made sure to continue reaffirming his status as a manservant by constantly setting him endless chores (The Coming of Arthur – Part 2). Before Arthur was crowned king, he finally called Merlin his friend, showing how close he had become to Merlin despite their differences. Arthur even hugged Merlin after finding him in the forest when he was kidnapped by Morgana, which is a notable display of affection since Arthur was unwilling to hug him when Merlin helped him prove to his father that his wife was a troll (A Servant of Two Masters, Beauty and the Beast – Part Two).

Merlin and Arthur

"You belong at Arthur's side. I've seen how much he needs you. How much you need him. You're like two sides of the same coin." —Hunith to Merlin

Merlin originally had an antagonistic relationship with Arthur, seeing him as nothing more than an arrogant bully and even saying that he'd help anyone who wanted to kill him. However, this changed quickly once he found out they were linked by destiny. Merlin became Arthur's manservant after saving his life for the first time. They have since become as close as brothers, and they constantly insult and bicker with each other like brothers. Arthur regularly threatens Merlin when Merlin treats him with disrespect, but Merlin remains unafraid of him and takes great pleasure in making fun of Arthur. Arthur in turn often abuses Merlin for laughs, such as giving him massive loads of chores to complete and notably pouring water on him several times.

Nevertheless, he admitted that some of his actions were "a bit unfair" when he tried to cheer Merlin up, unaware that it was the loss of Freya and not his pranks that was upsetting Merlin (The Lady of the Lake). There are also things that impede their relationship and make it difficult for them to be proper friends to one another. Firstly, they are separated by their differences in status. As a prince, Arthur is expected to treat those of lower class, like servants, with less respect than those of a higher class. They are not supposed to see each other as equals and so this causes problems in their friendship. There is also the issue that Merlin has hard time confiding in Arthur, as he couldn't speak of some of the biggest upheavals of his life despite Arthur's urging (leaving Ealdor, his magic, Freya's death, his father's death, Morgana's fall) due to the fact they might raise suspicions of his magic. Arthur, on the other hand, seems to trust Merlin with most of his secrets, including disguising himself to fight as another knight in a jousting tournament (The Once and Future Queen), his feelings for Gwen, and his many secret missions such as helping Mordred and going to see Morgause (The Beginning of the End, The Sins of the Father).

Despite such constraints and differences, Merlin and Arthur have proven loyal to each other and to their friends. From the outset, knowing that he must protect Arthur for his "destiny," Merlin had been willing to sacrifice his life for Arthur ( The Poisoned Chalice, The Labyrinth of Gedref, Le Morte d'Arthur, The Last Dragonlord, The Darkest Hour). Morgause notes this remarkable feature as she threatened him, but Merlin refused to say a word about it (The Tears of Uther Pendragon). Merlin had repeatedly claimed that he believed in Arthur's future to be a great king and rule Camelot with justice. For this, he is willing to disguise himself as a servant and secretly save Arthur's life for no credit. Arthur, in return, had proven that he had no second thoughts about risking himself when Merlin's life was in danger, in spite of his father's disapproval and orders (The Poisoned Chalice, The Moment of Truth, The Labyrinth of Gedref). Merlin now considers Arthur a friend regardless of position and uses this to advise him which in turn Arthur respects and is grateful for. Arthur has sought Merlin's council on a broad range of subjects, from the truth of his birth, the right thing to do politically, how to express his feelings toward women and which shirt to wear to a banquet. Several times he has expressed admiration for Merlin's wisdom, though each time in a rather indirect fashion. Arthur also allowed Merlin to sit at the round table, showing that he respected and trusted him as much as his most trusted knights. Apart from Gwen, he was probably the only other person of his class who had a real influence on the prince. In Series 4, Merlin and Arthur became closer and Arthur admitted that Merlin was a brave man. Merlin then risked his life by sacrificing himself to protect Arthur again. Arthur planned to return Merlin to Camelot so that Gaius could cure him but Lancelot offered to take him. When Uther was mortally wounded by an assassin, Arthur planned to use magic to save him and Merlin saw this as a chance to convince Arthur to return magic back to Camelot. Merlin, however failed to save Uther and was forced to escape. Before Arthur was crowned king, he finally called Merlin his friend, showing how close he had become to Merlin despite their differences. Arthur even hugged Merlin after finding him in the forest when he was kidnapped by Morgana, which is a notable display of affection since Arthur was unwilling to hug him when Merlin helped him prove to his father that his wife was a troll (A Servant of Two Masters, Beauty and the Beast - Part Two). Later, when Camelot was recaptured by Morgana and Helios, Arthur lost his faith and believed himself unworthy of the role as King. Merlin helped restore his faith by convincing Arthur to draw Excalibur out of the rock Merlin had forced it into. Merlin and Arthur soon overthrew Morgana.