Spoiler Warning: ⚠️ If you have seen Dark and Merlin then great read on! If you have only seen Dark then this won't mean much to you as a post but if you have only seen Merlin and have no interest in watching Dark in the future then you can also read on too I guess.
Merlin mirrors Dark they both have an incapable tragedy which I've just realised.
Merlin is told by a higher authority (the Dragon) that he has a grand, capital-D Destiny: protect Arthur, bring magic back, and unite Albion. He spends five seasons executing that "prophecy".
But just like Jonas, Merlin falls into the self-fulfilling prophecy trap. In his desperation to stop the bad things from happening (like trying to stop Morgana or Mordred because of what the dragon foretold), Merlin's own secretive, paranoid actions are often the exact things that push them into becoming villains in the first place.
By trying to "fix" the future, he accidentally paves the road right to it. Arthur dies before the golden age truly starts.
You can choose to believe that Arthur has already fulfilled the prophecy and united the lands of Albion which is viable because it was his destiny to unite them not rule them.
So looking at the bigger picture, Merlin did unite the peoples of Albion through his journey; it just didn’t look like the happy, victorious kingdom he thought he was building.
The Kilgharrah / Adam Manipulation Theory
The fan theory that Kilgharrah (The Great Dragon) is the true villain is one of the most fascinating ideas.
When you look closely, his role maps perfectly onto Adam in Dark:
The Massive Vendetta: Kilgharrah was locked in a cave for 20 years by Uther, who slaughtered his entire species. He has every reason to want the Pendragon dynasty completely wiped out.
The theory suggests Kilgharrah didn't feed Merlin prophecies out of the goodness of his heart.
He used an impressionable, powerful young boy as a weapon. By giving Merlin riddles and telling him who to trust or kill, he puppet-mastered the entire fall of Camelot from his cave.
The Parallel to Adam: Just like Adam uses Young Jonas’s desire to "do the right thing" to ensure the apocalypse happens, Kilgharrah uses Young Merlin’s loyalty to ensure Uther’s line suffers.
Whether you fully believe the dragon was evil or just an ancient being speaking in absolute cosmic rules, the dynamic is exactly the same.
The characters are just pawns being moved across a board by a player who has already seen how the game ends.
However Merlin is not Dark despite them both being tragic in genre, Merlin is a feel good and Dark is a feeling weird.
So I present this final reverse psychology theory to all you Kilgrarrah haters and Kilgraah defenders alike.
If Kilgharrah was just a malicious puppet-master trying to destroy the Pendragons to bring about a golden age of magic, then his grand plan was a total failure.
When we see an immortal Merlin walking past Glastonbury Tor in the modern day, magic is completely gone.
It is a world of trucks, asphalt, and ordinary humans. If the dragon was manipulating things to create a permanent magical utopia, it didn’t work.
This might suggest Kilgharrah wasn't lying; he was just enslaved to the same tragic parameters of prophecy that Merlin was.
He truly believed Arthur was the key, but prophecy is a slippery, ironic thing. Arthur did unite the lands of Albion structurally, but the "Golden Age" they built was short-lived, and magic ultimately faded away into myth and history anyway.
'Arthur was destined to unite the lands not rule over them' theory supports this.
The real tragedy of Merlin's modern day magic being lost forever in that fictional reality is what makes Merlin go from a fun fantasy show to a profound masterpiece.
Quite similar to Dark but less depressing. (Please gng I haven't seen season 3 of Dark yet so no spoilers but I can already deduce these parallels).
The ending tells us that the battle was won, but the world changed anyway. Merlin did everything right. He saved Arthur a thousand times, he united Albion, and he became the greatest sorcerer to ever live.
But time is the ultimate conqueror. Dynasties fall, kingdoms fade, and magic eventually dried up, leaving Merlin as a lonely, immortal relic of a forgotten age, still waiting by the lake for a king who will likely never return.
It is beautifully tragic, and it connects right back. Sometimes the characters give absolutely everything they have to a cosmic cause, and while they technically fulfill the "prophecy," the universe resets or moves on in a way they never could have predicted.
Is Merlin underappreciated?
It layers these massive, brain-bending themes of fate beneath what looks like a simple, charming Saturday-night fantasy show.
And if your still hooked on the theory that Kilgarahh is in fact evil then I guess you could argue he thought Arthur's death would bring magic back to Camelot but the fact that it doesn't end up happening this way doesn't necessarily exempt Kilgarrah from this intention.
Personally, The Great Dragon's wise words will always convince me that he was just a victim of fate even though he believed he could control destiny.
Merlin tried desperately to save Arthur Pendragon, only to be told by Kilgharrah: “Merlin, there is nothing you can do.” After Merlin insisted he had failed...
Kilgharrah replied with such depth and reassurance: “No, young warlock. For all you’ve dreamt of building has come to pass.”
Still, Merlin couldn’t accept it: “I can’t lose him… he is my friend.”
“Though no man, no matter how great, can know his destiny, some lives have been foretold, Merlin. (Fate - like in Dark everything is already written).
"Arthur is not just a king; he is the once and future king. Take heart, for when Albion’s need is greatest… Arthur will rise again." (Even if not literally).
"The story we have been a part of will live long in the minds of men."
It has because of this created a show with an incredible undeniable narrative bending spin to a beloved historical legend. If you didn't understand the point of the ending I would say this is it.
People who say they were promised a 10 season Small ville style origin story clearly didn't notice these obvious hints to the subtext of the inevitability of fate which seems to make this show despite it being not what some fans expected.
Whatever your interpretation of the show, if you look at it differently now, then surely I've convinced you just how awesome it is!