That is why it completely blindsided everyone when Mordred mortally wounded him in the Season 5 finale. Merlin tried to do everything to save Arthur, even revealing his magic to the king. Unfortunately, there is nothing Merlin can do to save him, and fans are forced to watch as Arthur slowly dies.
Reasons for Arthur's death in the Merlin TV show: Adherence to the Arthurian legend: The creators of Merlin wanted to tell the legend of King Arthur as it was traditionally known. In many versions of the Arthurian legend, Arthur dies in battle or as a result of a wound inflicted during a battle.
Anyway, she has a lot to prepare for her coronation, and according to Merlin and Gaius, Arthur will rise again. This eases her grief. In the afterlife, Uther hurries to the gates of the Spirit World, awaiting Morgana and Arthur who he had seen dying through his magical crystal ball in the afterlife.
In the Tavola Ritonda, Camelot is abandoned and falls to ruin after the death of Arthur. From Geoffrey's grand description of Caerleon, Camelot gains its impressive architecture, its many churches and the chivalry and courtesy of its inhabitants.
In the Perceval en prose (also known as the Didot Perceval and also attributed to Robert), where Merlin is the initiator of the Grail Quest and cannot die until the end of days, he eventually retires after Arthur's downfall by turning himself into a bird and entering the mysterious esplumoir, never to be seen again.
The Death of Merlin...and Why the Wizard Didn't Stop It! - European Arthurian - Extra Mythology
Why did Merlin end so abruptly?
Why was the TV series Merlin canceled? They always planned it the way it was. It wasn't canceled it just ended. The writers always said they only ever planned for five seasons.
While Guinevere was locked in the Tower of London, King Arthur fought Mordred to regain his throne. Both King Arthur and Mordred died in their battle with each other. After King Arthur died, Guinevere joined a nunnery and stayed there until her death. She was buried next to King Arthur.
What happened to Guinevere and Lancelot after Arthur's death?
Le Morte d'Arthur
When Launcelot hears of the death of Arthur and Gawain, he comes to England in haste. He looks for the queen and finds her in a nunnery. For love of Guinevere as much as for remorse he takes on the habit of a priest. Guided by visions, he goes to Almesbury, where he finds Guinevere dead.
Guinevere is childless in most stories. The few exceptions of that include Arthur's son named Loholt or Ilinot in Perlesvaus and Parzival (first mentioned in Erec and Enide).
At the end of the series you see an old Merlin in modern day UK (Albion) which means he succeeded. There were many "Arthurs" per se and Merlin was to continue to help that King every step till the next and so on and so forth until Albion was finally united.
Awoken is the first ever episode of the first series, Series 1 of Camelot: the New Age, a Merlin spinoff. This episode features the start of Hana's adventures in Camelot as well as marking the first appearance of Lucas, Annabella, Merlin, Arthur and Gwen.
Mordred's family is a particularly important part of his story. According to most versions of the legend, Mordred is the son of King Arthur and Morgause, who are half-siblings. This means that in addition to being King Arthur's son, Mordred is also King Arthur's nephew.
Arthur, son of Igraine and Uther Pendragon, is thus Morgan's half-brother, and her full sisters include Mordred's mother, the Queen of Orkney. The young Morgan unhappily marries Urien, with whom she has a son, Yvain.
One of the sole reasons Morgana turned into a villain was because she was corrupted by Morgause. With Morgana in Morgause's company for a year, the witch successfully brainwashed her sister into believing Uther and Arthur were the real evil.
Morgana catches up with Merlin and Arthur and drives their horses away, but she is killed by Merlin wielding Excalibur. Without horses, Merlin cannot get Arthur to the Isle in time, and Arthur dies in Merlin's arms, after thanking his friend for everything he has done.
She was a beautiful and noble queen, but her life took a tragic turn when she fell in love with Lancelot, one of Arthur's bravest and most loyal knights. The relationship between the queen and Lancelot eventually destroyed the special fellowship of the Knights of the Round Table.
The Brut Tysilio makes Gorlois also the father of Cador, who is thus Arthur's half-brother through Igraine; Cador's son Constantine succeeded Arthur as king of Britain in the Historia Regum Britanniae. Various works mention or feature Arthur's nieces and occasionally also different nephews.
Merlin later makes some tellings of the future, and is allowed back into the forest. Before he leaves, however, he goes to talk to his wife. His wife's name was Gwendoloena, and she lived together with Merlin's sister.
Though one of the Welsh Triads (Triad 56) speaks of Arthur's three great queens (all named Gwenhwyfar), later romance generally gives him only one wife named Guinevere. Geoffrey of Monmouth introduces the notion of Guinevere's infidelity (with Modred) while Arthur is fighting on the continent.
King Arthur marries Guinevere, daughter of the King of Scotland. Merlin tries to warn him against the marriage because Guinevere is in love with Sir Lancelot, one of Arthur's knights.
How did King Arthur find out about Lancelot and Guinevere?
Though Lancelot is loyal to Arthur and Guinevere's marriage to the King takes place as planned, it is not long before the two become lovers. Modred spies on them and informs Arthur of his wife's infidelity. Lancelot escapes, but Guinevere is condemned to be burned at the stake.
Both the Myrddin of the early Welsh poems, then, and the Merlin of Vita Merlini, were depicted as wild men and prophets. Each of them had taken part in a battle which caused him to slip into madness, and to flee into a forest where he lived as a wild man.
Old Merlin, otherwise known as Emrys, is Merlin's alter ego. The young warlock uses an aging spell to transform himself into an old man and must take a potion to transform back to his young self. Gaius is the only one to know Old Merlin's true identity.
Arthur was unaware of Merlin's powers until the very last episode of season 5 ("The Diamond of the Day: Part 2). In one of Merlin and Arthur's best moments, both men share a beautiful but bittersweet conversation as Arthur's discovered everything Merlin had done and sacrificed for him.
