"Arthur how is it even humanly possible to have this much paper work?" Merlin groaned as he signed off yet another import export form only to find another seventy waiting for him.

"Joys of being a prince..." Arthur sighed, "At least you're not regent."

"Yeah, let's keep it that way." Merlin sighed.

"Sire!" Came a guard as he burst into the room, "It's you're brother he's-what?"

The guard looked confused to see Merlin sitting there with his brother at his desk.

"I'm what?" Merlin asked.

"Well, you were attacking the king with magic..." The man gaped, "How did you get here?"

The princes didn't bother to answer before taking off towards their fathers room, as they closed in the sound of yelling could be heard through the slightly opened door. Merlin pushed his way into the room and tried to fathom what he was seeing.

Uther was on the floor by the window looking as terrified as the time Morgana had meddled with his mind, eyes blown and breathing erratic. In front of him was, himself with blazing gold eyes, sneering down at his father like an insect.

"Say goodnight Uther, I'm taking over this kingdom myself." The fake Merlin sneered.

Uther looked and saw the real Merlin and blinked in shock, Uther had only just started to heal, this would set him back months! Merlin was frozen in shock allowing a guard to rush forth and stab at the fake Merlin only to have it dodge and transform before their eyes into the largest black snake the prince had even laid eyes on.

"What?" Arthur gaped when he entered the room just as the guard ran out of it screaming like a girl, the giant snake following him and disappearing down the stairs. Arthur shook his head in disbelief while Merlin went to his fathers side.

"It wasn't real...?" Uther questioned, "You were there and here at the same time..."

"A trick, just a magic trick." Merlin assure, "Come on father, you should rest."

...

"A boggart?" Arthur asked, "What in the world is a boggart?"

"A creature of magic." Gaius replied, "It takes the form of what ever you fear the most. For Uther it was Merlin turning to magic, for that guard a snake."

"How do we get rid of it?" Merlin questioned, "We can't have it running loose around the castle!"

"Boggarts like dark, dank places, that's probably why it ended up in Uther's chambers." Gaius theorized, "It's probably been living in the vaults."

"So can we kill it with a sword?" The young prince asked hopefully.

"It's a hard job, you need to weaken it first or it will just change into something else." Gaius sighed, "They are dark and tricky creatures."

"How do we weaken it?" Arthur asked.

"You must appear unafraid." Gaius replied, "If the boggart think it is not scaring you it will change into something else and eventually become confused, that is when it's at it's most weak."

"So it's going to change into what frightens us most and we have to pretend not to be scared?" Merlin gaped, "How?"

"That is something you must figure out for yourselves."

...

The next week was a stressful one, guards places lanterns and fire pits all over the castle but still the boggart found it's way around. All day and night you could hear people yelling and screaming at all manner of monsters. Giant snakes and spiders, rooms filling up with water, floating swords, ghosts, ghouls and even a manticore at one point. Every time the princes arrived the creature was gone. Arthur felt as if he was constantly on-guard, his sleep was lighter than it had ever been, which is why he was easily awakened by a scream from Merlin's chambers down the hall.

"ARTHUR!"

"Merlin!"

When Arthur made it into the room he didn't see anything out of the ordinary, save Merlin who was backed up against the desk shaking like a leaf.

"I-it went up the ch-chimney..." He stammered, "The boggart, I didn't realize..."

"It's alright." Arthur breathed as he helped Merlin up, "What did you see?"

Merlin just shook his head, try as he might the elder prince couldn't get the warlock to admit what had frightened him so.

...

A few days later their luck finally came through with Leon announcing that they had cornered the creature down in the dungeons, Gwaine was keeping it busy. That was worrying. When they two made it down to the dungeons they were hardly surprised to see Gwaine trapped in a cell surrounded by hundreds of empty bottles of ale and being forced to drink water. When Gwaine stopped and took a few deep breaths the barrels disappeared in a strange twisting wind and changed into a very large scaly dragon which started to stalk Leon.

"We all have to stop being frightened of what it shows us!" Arthur yelled, "Or at least trick it."

"Ummm..." Leon stammered as he ended up backed against a wall with the dragon forming smoke from between it's teeth.

"Remember Leon we beat a dragon before!" Lied Merlin, what Leon didn't know wouldn't hurt him. Leon struck out at the dragon which growled with annoyance, the knight grinned.

The knights and the dragon dueled for some minutes before the monster swung it's tail out and knocked both Gwaine and Leon out cold. Leaving it with the two princes.

The dragon turned to Merlin, sizing him up before it began to twist and change, not surprising to Arthur in the least, the last thing Merlin would be afraid of, is a dragon. The prince held out their swords in the defensive stance, waiting for the transformation to form. Arthur almost dropped his sword when a perfect copy of himself formed.

"You're going to the pyre sorcerer!" Spat Not-Arthur who was being joined by copies of the Knights of the round table, Uther and Gwen. Merlin's hand shook eventually causing him to drop the sword and backed down.

"Merlin, I'm right here!" Arthur cried, "It's a fake, remember?"

The warlock took a deep breath and closed his eyes for a second, when he opened them again they were clear of fear. Instead they were steely and straight. Fake Arthur's entourage disappeared and he sneered, turning to the real one. Uh oh.

Arthur got ready to face his fear, unsure as to what it would be, probably his father berating him or even worse, dis-inheriting him. What he wasn't equipped to handle however was the form of Merlin with a deep wound in his side. He looked pale and weak, exactly as he had before Morgana pushed him out the wall and into the swollen moat last year.

"Why didn't you save me?" Not Merlin yelled accusingly, "You're m older brother, you're supposed to protect me!"

"I...I um..." Suddenly the princes mouth had turned to sand paper.

Merlin, the real one acted for his brother and swiping at the fake Merlin who hissed at him in a very un-Merlin like manner. Arthur snapped out of it.

"I'm not afraid of you." Arthur laughed, actually laughed, "The real Merlin is right here! You can't scare us when we're together."

The boggart got desperate, it changed into a snake, then a spider, then a dragon and when none of them induced a single flicker of fear in the princes it got stuck somewhere in between them all.

"Would you like to do the honor?" Merlin offered, handing Excalibur to Arthur from where he'd dropped it.

"Don't mind if I do." He replied, swiftly stabbing the boggart through the middle and making it explode into a cloud of ash and fire.

Explanation of fears:

Uther: Morgana turned evil with magic and because he knows Merlin has it he is afrad he'll loose another child that way.

Gwaine: I wanted a funny fear and that was in character.

Leon: He was the only person besides Merlin, Uther and Arthur to survive the dragon attack.

Merlin: Fear of rejection due to his magic has been ingrained into him ever since birth and Arthur is the person who means the most to him. So his rejection would be the worst.

Arthur: Loosing Merlin was very hard for him and he would never wanted to feel that way again. Plus I wanted both brothers to have a fear to do with each other.