"Dragoon the Great" is a disguise that Merlin uses to mask himself, to prevent his magic from being discovered by others. This disguise is created by an ageing spell that makes him appear about eighty years older. The name, which Merlin thought up on the spot, may be a bastardisation of "The Great Dragon". In his disguise, he is mostly referred to as Emrys by the Druids and also by Morgana. He is the great nemesis of Morgana and is very much feared by her. It seems to be an allusion to the old Merlin of Arthurian Legend.
The disguise first appears to Merlin when he is in the Crystal Cave, witnessing future events in the crystals (The Crystal Cave).
When Gwen was accused of enchanting Arthur, though it was actually Morgana's doing, Merlin felt the need to save her from execution. Morgana had planted a poultice in Arthur's chambers so she could use that against Gwen. So, he decided to disguise himself as an old sorcerer, the same one he saw at the Crystal Cave, to lift the sentence off Gwen. Merlin had requested Gaius to make an ageing potion, and upon taking it, he transformed into an older version of himself. He then asked Gaius to make a similar poultice to the one Morgana had used previously. Then, he set off to get caught deliberately. He deliberately allowed Arthur to spot him planting the poultice in his chamber. Arthur immediately drew out his sword. Merlin stopped Arthur by announcing if he were to run him through with the sword then Arthur would never learn of his "plan". Arthur then lowered his sword and looked at the the old warlock, Dragoon, with curiosity, recognizing his eyes. Dragoon cast a spell, temporarily knocking Arthur out with a helmet to his head, and made a run for it. Shortly afterwards, when Merlin tried to use the reversing spell, it had no effect. Arthur and a few guards caught up to Dragoon and Arthur brought him to Uther, to whom Merlin, as Dragoon, finally spoke his mind and lifted the blame from Gwen. He took Gwen's place and was taken to execution the next day, despite having tried to distract Arthur with more "confessions". Gaius visited him in the cell and Merlin told him he was unable to turn back. Gaius said he could save him by brewing a potion that reverses the effects. He found time to give it to Merlin, who once again tried to escape. He drank the potion, returning to his normal appearance. In the end he saved Gwen, but nearly got himself executed in the process (Queen of Hearts).
When Morgana discovered from The Cailleach that Emrys was her doom, she had a dream of the future which showed her pleading to an old man, whom she called "Emrys", in a battle. However, she didn't know that she was dreaming of Dragoon The Great. (The Darkest Hour).
When Uther was dying and Arthur seeking magic to save him, he and Merlin went to 'Dragoon's hut', but Merlin quickly snuck into a bush because he needed to 'pee'. He instead took the potion that transformed him into 'Dragoon'. Arthur struck a bargain with the old sorcerer. The bargain was that if Dragoon saved Uther with sorcery, Arthur would allow magic to be practiced in Albion. They met up at the lower gate to Camelot and made their way to Uther's chambers. Merlin tried to save Uther but, little did he know, Morgana had had Agravaine put a necklace on Uther that blocked any curing spells and reversed and strengthened their effects. Merlin, in his disguise as Dragoon, managed to save Uther for only a few seconds before Uther finally died. Arthur went on a rage but Merlin (who was possibly even more upset) cast Arthur back so that he could escape. This only increased Arthur's hatred of magic (The Wicked Day). Gaius later mentioned to Arthur that the old man didn't intend to kill Uther, and did all he could in his power to save him but Uther was dying and nothing could be done (The Secret Sharer).
When Merlin needed to destroy the Fomorroh in Morgana's hut, he needed to once again disguise himself as Dragoon. On the way to Morgana's hut, he came across the Knights of the Round Table. They threatened to kill him but Merlin used magic to get himself out of the situation, knocking the knights out and using them as steps to get onto his horse. When he arrived at Morgana's hut, he searched for the Fomorroh, but Morgana returned and he was discovered. She tried to kill him with a knife, so he used a spell to push her back before a magical duel broke out between them. After several close calls, Merlin finally defeated Morgana with a powerful wind spell and killed the Fomorroh in a fire (A Servant of Two Masters).
Merlin appeared as Dragoon in a flashback following Morgana's magical duel with him (The Secret Sharer).
Merlin disguised himself as Dragoon for the fifth time when Morgana crowned herself queen again. He did it to plant a poppet under Morgana's bed, which blocked her magic so she couldn't kill Arthur during his confrontation with her. Merlin intentionally let Morgana spot him while he was disguised as Dragoon in order to lure her to "the safety of her bed", when in fact it was to the endangerment of her magic as Merlin had intended (The Sword in the Stone).
Merlin disguised himself as Dragoon for the sixth time when Gwen and Morgana were hatching a plan to kill Arthur. They had already poisoned him and let Merlin take the fault for it. He was put into the cells under the Queen's orders. He needed to get up to Arthur's bedroom, heal him, and go back to the cell before anyone noticed. Before he reached Arthur's bedroom he had a quick conversation with the cook, Audrey. Calling her food names caused Audrey's face to turn red. Eventually, he knocked her out with a pan. After that, he changed back into his real form and climbed up the wall to Arthur's chambers. He succeeded in reviving Arthur and quickly hurried back down to his cell (A Lesson in Vengeance).
Merlin disguised himself as Dragoon again in order to protect his true identity from being revealed to the Dochraid, when he had to get information from her in order to learn how to break the Teine Diaga, the magic Morgana was using to have Gwen under her control. He also took the Excalibur with him, to protect himself, when the Dochraid would threaten him with any harm. The Dochraid did not accept Emrys' presence in her cave, and she said she would not help him, and then Merlin threatened her with Excalibur, with her claiming that he cannot wield such a weapon. Emrys then wounds the Dochraid with the sword and the ancient creature very reluctantly explained the way of breaking Morgana's control over the Queen of Camelot. When Dragoon was departing the cave, the Dochraid, fearing that she has put herself and Morgana in danger, prepares to kill the disguised warlock by throwing a dagger at him by using magic. Merlin fortunately deflected the dagger and once again wounded the Dochraid with Excalibur, this time more seriously causing it to take time for her to recover and heal herself (With All My Heart).
During the Battle of Camlann, when Morgana used a creature to draw the magic from Merlin, as she knew of his true identity Merlin rushed to the Crystal Cave to get his powers back. However, Morgana learned of this and she trapped Emrys inside forever. However, after seeing the Spirit of his Father, he started to believe in himself and regained his magic. Merlin then disguised as Dragoon for the last time to help Arthur and his men win the battle. When their situation was becoming desperate, Dragoon used the full power of his magic to stop Morgana's and Mordred's men and kill them. He also knocked out Morgana. However, he failed to stop Mordred, who already stabbed Arthur with a "false Excalibur" and later died at the hands of the wounded Arthur. He then later, as his normal self, revealed his magic to Arthur because he had to take him to Avalon to heal him. Guinevere also learned the truth of Merlin's identity from Gaius. Unfortunately Arthur died on the way, but Kilgharrah told the young warlock, that one day the Once and Future King will rise again. In modern times, an old immortal Merlin still awaits the resurrection of Arthur, but there is still no sign of it (The Diamond of the Day).
Haughty, blunt and domineering, but fundamentally no less honorable a man than he normally is, in his guise of Emrys, Merlin has little use for his usual courtesies, as the fact that almost no one are aware of who he truly is allows him to ignore social customs and the hierarchy of nobility without having to worry about retribution for such insolence towards people of a higher station. Snide and sarcastic, Merlin very much embraced this newfound freedom and took obvious joy in the opportunity for him to not only practise his magic unhindered, but also to mischievously and, it should be said, somewhat pettily, get back at those who have laughed at and ridiculed him in the past, though never severely injuring them while doing so. Evidently fond of the looks on people's faces when confronted by them, Merlin also greatly plays up whatever eccentricities that befits an old man to have that came to mind, amusing himself by leaving people dumbfounded by a combination of magical mischief, taunting remarks and improvised pandemonium. That is not to say, however, that he never can pull himself together while adorning the mask of Emrys. Fully capable of staying within the character he created while also adopting a much more serious and determined persona in grim time and dire situations, eventually, he became recognised as a man who would readily use his considerable power to preserve the peace and prosperity of the realm, displaying an undeniable willingness to step forth to vanquish the enemies of the kingdom with such ruthless efficiency that he soon came to be held in great fear by many people; magic users and non-magic users alike. Ultimately recognised by people such as Arthur for being someone who would rather use his magical ability for good rather than bad, however, his integrity was so reputable that Arthur agreed to seek him out.
As Emrys, Merlin can use his magic without the inhibiting fear of discovery. In this disguise, he displays tremendous magical affinity. He is particularly adept at elemental magic, which seems to be his forté. He is able to conjure a colossal whirlwind in order to combat Morgana as well as use very powerful non-verbal stunning spells. At the Battle of Camlann in particular, upon accessing his full power in the the Crystal Cave, Emrys uses extremely powerful non-verbal lightning spells against the Saxons, with each bolt wiping out at least a hundred men, which is magic unlike anything else seen in the series. (By comparison Morgana, the second most powerful sorcerer in the series and the only other to use lightning spells, can only incapacitates several people directly in front of her with her lights)
- The Crystal Cave (Appears in crystals) (cameo)
- Queen of Hearts
- The Darkest Hour: Part One (Appears in visions) (cameo)
- The Wicked Day
- A Servant of Two Masters
- The Secret Sharer (Appears in flashbacks)
- The Sword in the Stone: Part Two
- A Lesson in Vengeance
- With All My Heart
- The Diamond of the Day: Part One
- The Diamond of the Day: Part Two
- A recurring gag over Dragoon is that, when Gaius has to explain Merlin's absence, he would simply answer that he is in the tavern and, as a result, Merlin got the reputation of being a drunk and is severely punished for that each time Gaius uses the excuse, much to Merlin's chagrin. This grows notorious to the point that Merlin asked Gaius to use another place than the Tavern as a excuse for his absence, but, unfortunately, Gaius refused and Merlin was forced to be "trained" by George for a week (A Servant of Two Masters).
- Another running gag that exists with Dragoon is that he often runs into nobles, namely Arthur and the Knights of the Round Table.