Title: The Houses of Pendragon, Emrys and Potter

Summary: AU OotP, set after M-S5. Merlin had always watched as the wizarding world fought for justice. He watched Harry Potter grow up as a young warlock struggling against Voldemort. At the Department of Mysteries on a Thursday evening when a deadly battle was playing out concerning Harry's destiny, Merlin decided it was time to step in. He will join the fight. This time. DISCLAIMER NOW!

Written by: Alexia Blackbriar (hoping to co-write with Holmes1216)

PLEASE REVIEW.

MULTI-CHAPTER STORY.

This will include Harry, Hermione, Ron, Ginny, Luna, Neville, Hedwig all of the members of the Order (including Sirius), the Professors, the characters from Book 5 and Book 6, Aithusa, Merlin of course and there will be mentions of Merlin S1,2,3,4,5.

DISCLAIMER: Some of this work belongs to the brilliant JK Rowling. I cannot take credit for her stuff! All the characters either belong to HER or the BBC.

A wave of powerful and strong magic rocked the Earth. Merlin looked up from where he had been seated, cross-legged, on the shores of the Lake of Avalon, staring out over the water. It had been five centuries since Arthur's death and the Battle of Camlann. He had gotten over his King's death a long time ago, but still liked to stay beside the lake because of the old memories that resided there.

The warlock instantly recognised the magic as New, but extremely powerful. Rising to his feet steadily, Merlin leant over the crystal clear water of the Lake and uttered a scying spell. He had been watching the magical society closely for many, many years. He had Seen the evil wizard Voldemort rise and witnessed the first battle between the Dark Lord and the Chosen One: Harry Potter, the Boy Who Lived. The Philosophers Stone… the Chamber of Secrets… the Triwizard Tournament and the graveyard… he had seen it all through the water, watched it happen, but had been unable to manipulate the events, as they were controlled by the Old Religion.

The water shimmered magically before revealing to Merlin the present. He instantly recognised the Department of Mysteries in the Ministry of Magic. Professor Dumbledore was duelling Voldemort brutally, while Harry was flung up against wall behind him, forced up against it as he gasped for breath, clearly exhausted. A fiery snake roared up before Dumbledore as both he and the Dark Lord shot ruthless and merciless spells at each other, faces contorted with pain and coldness towards each other.

Merlin swiped his hands through the water and the image vanished. The magic of the Old Religion burned within him, squeezing his heart and causing him to inhale sharply and deeply. It was time. It was time for Merlin to become part of this magical world. It was time for him to connect with the magical community, time for him to be seen again. For so long he had hidden by the Lake of Avalon, unknown and unseen, thought to be dead. But… it was time now.

His expression serious and determined, Merlin flung his hand out over the water. A beautifully crafted sword leapt from its depths, shining brightly. Excalibur gleamed in Merlin's hands and the warlock could not help but smile proudly. This was King Arthur's sword; the sword that had killed the traitor Mordred and the witch Morgana.

It was time to join the battle.

Another jet of green light flew from behind the silver shield. This time it was the one-armed centaur, galloping in front of Dumbledore, that took the blast and shattered into a hundred pieces, but before the fragments had even hit the floor, Dumbledore drew back his wand and waved it as though brandishing a whip. A long thin flame flew from the tip; it wrapped itself around Voldemort, shield and all. For a moment, it seemed Dumbledore had won, but then the fiery rope became a serpent, which relinquished its hold on Voldemort at once and turned, hissing furiously, to face Dumbledore.

Voldemort vanished; the snake reared from the floor, ready to strike –

There was a burst of flame in midair above Dumbledore just as Voldemort reappeared, standing on the plinth in the middle of the pool where so recently the five statues had stood.

"Look out!" Harry yelled.

But even as he shorted, another jet of green light flew at Dumbledore from Voldemort's want and the snake struck –

"Hilderand!" The snake smashed into a powerful, invisible shield and vanished within seconds. "Astríce!" the man bellowed, appearing out in a tornado of swirling leaves and wind in front of both Harry and Dumbledore as his eyes flashed liquid gold.

Voldemort's eyes grew wide with fear and shock as the force of the Old spell slammed into him, sending him flying backwards, flailing helplessly before smashing onto the tiled floor, unleashing a cry of agony. Harry gasped while Dumbledore stared. The man lowered his hand, his eyes returning to their natural cobalt blue, glittering as the stunned Voldemort staggered to his feet, laughing as though in complete astonishment. The man glowered at him, eyes filled with hatred. Voldemort's laugh quietened until it was merely a resounding chuckle.

"So, the great warlock finally shows his scrawny little face." Voldemort taunted the new-comer. "After all these years hiding…" His laugh was cruel and malicious and he gazed eagerly at the man with longing and envy. "Everybody thought you dead, but you were always there, waiting in the shadows."

The man glared at him. "It was not yet time for me to reappear." He informed the Dark Lord gravely in an emotionless, cold voice.

"And yet now, it appears that it is." Voldemort cocked his head sideways at the newcomer, curious. He now had no interest in Dumbledore or Harry and instead seemed fascinated by this new man. "Join me." He urged the man. "Join me, and we shall triumph! The Old Religion will flourish once again and I will rule over magical and non-magical people alike. You will be powerful once again!"

The man stared at him disbelievingly before bursting out laughing. Harry couldn't believe his eyes or ears. This man, who looked around nineteen or twenty years old, with very powerful magic of the likes he had never seen before, was laughing at Lord Voldemort. Laughing.

"ME, join YOU?" the man laughed, as if I was some kind of joke. "Are you utterly insane?"

"Are you?" Harry hissed.

"Why do you mock me so?" Voldemort demanded. "Join me!" he practically screamed.

"You know who I am." The man said, now serious. "You know I would never join you."

Voldemort's eyes hardened. "Then if you will not join me," he hissed, "Then I will have to kill you."

Furiously, he flicked his wand towards the man and Harry held his breath in fear as a jet of green light hurtled towards the newcomer. The man barely blinked and instead simply raised his hand. Dumbledore and Harrys' jaws dropped in astonishment as the killing curse merely extinguished a metre away from the man's hand.

"Impossible." Dumbledore murmured.

Voldemort screamed in frustration: "Evada Kedavra! Stupefy! CRUCIO!"

All the spells simply disintegrated in front of the man. He even laughed. His eyes flickered golden for a few seconds as he sent Voldemort stumbling back a few steps, eyes wide with terror at the thought of being weak.

"Forebærne." The man whispered, thrusting his hand outwards. A large, flaming fireball soared towards Voldemort, hitting his square in the chest. The smell of burning flesh filled the air and scraps of black robes were thrown onto the floor and Voldemort scratched at him burn mark, screaming.

There was another shriek of outrage as he pointed his want at the man furiously. "CRUCIO! CRUCIO! EVADA KEDAVRA!"

"Forfylden." The man murmured, his eyes glowing topaz. Once again, the curses had no effect.

Voldemort screamed again, a shock wave sending glass splintering and the shards flying across the hall like knives. Order of the Phoenix members sprinted into the chamber, eyes wide with fear, squeaking when they saw Voldemort; the Minister of Magic appeared out of one of the fireplaces and gasped when he saw the Dark Lord there, standing a few metres away from him.

Yelling furiously, Voldemort vanished in a burst of fire that quickly transformed into a flame serpent that hissed threateningly at the three of them before disappearing in cloud of smoke.

Harry rose to his feet uncertainly, helped by Dumbledore; the stranger stood, motionless. DA members began to appear behind the Order; Hermione and Ron sprinted towards Harry, embracing their friend tightly while he shook in half-fear, half-relief. Ginny, Luna and Neville raced to meet them and hugged them all, laughing in relief. Fred and George, who had arrived quite suddenly, clapped Harry on the back, smiling broadly as they congratulated him gleefully. However, Harry couldn't feel any glee at all; he allowed tears to flow down his face as he remembered his godfather's face as he died, the shock that had lingered in his eyes before being replaced with an eerie peace.

Nobody noticed the powerful warlock who had fought Voldemort back up against the wall and slide down the side of it, eyes scrunched up in pain as gasping as he hit the floor. Voices swam around him and the people surrounding him were blurred. Grimacing, he gritted his teeth and closed his eyes, swallowing heavily.

Fudge was arguing hysterically with Kingsley while Tonks and Lupin were sorting out some of the other Ministry officials. Harry cried while his friends hugged him. Professor McGonagall and Molly Weasley promptly arrived and began fussing over them, checking them over for injuries. Dumbledore was standing in the middle of the hall, flourishing his wand as he repaired the chamber and the statues of the fountain.

Merlin reached down towards his belt and caught hold of the invisible sword sheath, drawing out Excalibur and staring at it with hazy eyes, holding Arthur's legendary sword in his left hand tightly, afraid to let it go. He clutched at his side through his red servant's shirt that he had worn everyday since Arthur had been killed.

He yanked off his blue neckerchief, smiling at it weakly, remembering how many times Arthur had teased him because of it, before placing it on his bleeding wound. Unbeknownst to the others, he had killed off more than a dozen Death Eaters before they had a chance to attack the DA or Hogwarts. He had been caught off guard when he had been hit with two curses at once: diffindo and stupefy at the same time, and they had torn his left side into pieces, shattered that side of his ribcage. It was too painful to move, to even think.

Memories clouded his mind.

He was leading Arthur through the forest, a determined look upon his face. Camelot had been taken by Morgana and Helios, and he, Arthur and Gwen, as well as two smugglers, Tristan and Isolde, were hiding in the Forest of Essetir. He had recently spoken to Kilgharrah about Arthur losing the will to fight but he had come up with a cunning plan.

"This had better be good, because this really isn't the time for one of your ridiculous games." Arthur growled unhappily, following his manservant through the woods.

"I was thinking about last night," Merlin explained, "And how you'd been saying you'd given up all hope, that you were a poor leader and a shoddy King…"

"Shoddy?" Arthur spluttered, eyebrows raised.

Merlin rolled his eyes. "Alright, shabby."

"Thanks." Arthur said sarcastically.

"Well, it reminded me of a tale Gaius once told me." Merlin informed him, looking around, searching in the trees.

Arthur shook his head, rolling his eyes: "Merlin, I'm really not interested in your favourite bedtime stories."

Merlin stopped, gazing out in the trees before turning around to face his grumpy master. "For once in your life," he said, biting back a grin, "Just LISTEN."

Arthur pursed his lips but spread out his hands, holding them up as he nodded, somewhat reluctantly. Merlin gave a small smile before turning back around and striding through the forest.

"Many years ago, before the birth of the Five Kingdoms, this land was in an endless cycle of bloodshed and war. But one man was determined to end all that. He gathered together the Elders of each tribe and drew up plans for the land to be divided; each would respect the others' boundaries and rule over the land they each saw fit." He was fully aware that Arthur was rolling his eyes and shaking his head, obviously annoyed, behind him. "That man was Camelot's first King." Merlin continued. "Ancestor to all that followed, including you, Arthur."

Arthur stated, in an irritated and tired voice, "Bruta."

Merlin nodded; "You know the story…"

Arthur rolled his eyes once more. "Yes, every child in Camelot does." He paused before adding, "Can I go back to bed now?"

"No." Merlin told him firmly. "Because there's another part of the story that you haven't heard."

"Really?" Arthur said sarcastically.

Merlin ignored his comments and continued, "When Bruta was on his death-bed, he asked to be taken deep into the forest. There, with the last of his strength, he thrust his sword into a rock. His lineage was never questioned; this would form a test. Only a true King of Camelot could pull the weapon free."

Arthur now walked beside him, disbelief written all over his face. "Are you making this up?"

Merlin tsked him. "Of course not." He lied, beginning to walk again.

Arthur raised an eyebrow at him before frowning, hurrying after his manservant. "Alright." He allowed. "If this is true why haven't I heard this story?"

"Well… history isn't really your strong point, is it?"

"Then where is this rock?" Arthur asked in an accusing voice.

"Oh, it was lost, many years ago." Merlin answered casually, walking down some steps, still leading Arthur onwards. "During the Great Purge. But – I've managed to find it." He sounded triumphant and proud of himself.

Arthur snorted. "I've never heard so much rubbish, in my entire life."

Merlin turned around, glaring, "Are you calling Gaius a liar?"

"No." Arthur cried out, offended by the idea. He stopped in front of Merlin, glaring at him. "I'm calling you an idiot!"

Merlin smiled before turning to motioning through the woods to a glade. "What's that then?"

Arthur shook his head before turning and staring through the woods where Merlin was looking. He stopped, his head hammering. His mouth slacked in disbelief. There, in the middle of the clearing, sat a large boulder. A beautiful silver sword, with a golden hilt that glittered in the sun, was stuck it in, its beauty shining around the glade. Arthur gazed at it, mesmerized, while Merlin grinned and led him forwards towards it. They stared at it a while, awestruck. Then, suddenly, figures appeared in the trees. People of Camelot and the Knights trekked down towards the clearing. Arthur and Merlin could see Percival and Leon leading them, helping some people get down a steep slope. Arthur stared at them all, shocked, before turning to Merlin, who had a pleased smirk on his face.

"What the hell are you playing at?" Arthur hissed at him furiously, fists clenched.

"I'm proving that you're their leader, and their King." Merlin said, grinning widely.

"That sword is stuck fast in solid stone!"

"And you're going to pull it out." Merlin told Arthur, certainty in his voice as he gazed at his master in respect.

"Merlin! It's impossible!" Arthur whispered.

"Arthur, you're the true King of Camelot." Merlin told him firmly, voice filled with confidence.

Arthur hesitated at his servant's tone, looking slightly touched, turning to look at his waiting people and the beautiful Excalibur before turning back to Merlin, who was looking at him like he was the greatest man he'd ever known, and that he'd lay down his life for Arthur.

"Do you want me to look like a fool?" Arthur asked, half-horrified and half-annoyed.

"No, I want you to see that Tristan's wrong." Merlin informed him, proudly. "You aren't just anyone, you are special. You and you alone can draw out that sword!"

Arthur paused once more, gazing at Excalibur, gulping, before yanking out his old sword and thrusting it into the ground beside Merlin. "You'd better be right about this." He whispered threateningly to Merlin, his face straight. The warlock only smiled.

Arthur strode forwards, gazing at his knights and people before fixing his hands around the sword uncertainly. He tried to yank it out with all his might, but only ended up wasting his strength. Merlin watched unworriedly. He knew Arthur had to believe.

"You have to believe, Arthur. You're destined to be Albion's greatest King." Merlin urged him. Arthur shook his head slightly, but Merlin continued, assuring him, "Nothing, not even this stone, can stand in your way."

Arthur stared at Excalibur and the stone. He briefly shut his eyes. He believed. He believed in himself. Reaching forwards with one hand, he grasped the sword as though he was going to pull it out of a sheath. Taking a deep breath, he closed his eyes and hoped.

"Have faith." Merlin murmured.

Lifting his head slightly, Arthur exhaled calmly, before drawing his arm upwards. Merlin's eyes burned gold. The sword slid out of the stone as if it was water and Arthur thrust it into the air, his eyes wide with triumph. Merlin gazed up at him in awe, as did Camelot's citizens. Leon and Percivals' eyes nearly popped out of their sockets.

"LONG LIVE THE KING!" Leon roared.

"LONG LIVE THE KING! LONG LIVE THE KING! LONG LIVE THE KING! LONG LIVE THE KING! LONG LIVE THE KING!"

Merlin awoke with a painful gasp. He remembered that story. That memory was extremely painful and caused his heart to ache. He turned over, tears filling his eyes, not even caring about the wound on his side.

"Hello." Somebody whispered to him.

He looked up through bleary eyes and saw Luna Lovegood gazing down at him. He blinked at her uncertainly, shifting away. His magic bubbled up inside of him, desperate to escape. The balance between Old Magic and New had been altered when he had entered the battle and it was draining his body of energy, clawing at his magic inside of him.

Luna gazed at him with dreamy eyes before turning around: "We need some help!"

Merlin flinched in pain as shadows flickered over him as Order and DA members surrounded him, some kneeling beside him and some just standing over him protectively. Dumbledore, who was crouched next to him, tried to reach forwards to touch his wound.

"Don't touch me." Merlin gasped in a strangled voice.

The Old Magic was flowing freely inside of his veins, coursing powerfully through his blood. He had to release it somehow. But he didn't want to risk hurting Harry or any of his friends so allowed it to swim around inside of him, burning and searing him agonizingly.

Dumbledore withdrew his hand, looking concerned. "Thank you." He murmured gratefully. "You saved all our lives."

"My pleasure." Merlin answered through gritted teeth. "Believe me, it's nothing new. I've been doing this sort of stuff for centuries."

He couldn't take it any longer. He had to release the Old Magic. He couldn't hold it back; he knew it would destroy all those in its path to reach the earth. If only he knew a way to channel it somehow. Wait. Wait. Sirius Black. He was dead. If Merlin could use his overflowing magic somehow… Reaching down within himself for something he had hidden away for centuries, Merlin drew his ability to mirror life and death to the surface. His magic swirled around it and Merlin centred his mind on Sirius' name.

He took the life of one of the Death Eaters that was dying slowly in the Department of Mysteries and allowed that life force to flow seamlessly into Sirius' body. He felt Harry's Godfather gasp for breath, his eyes flying open in shock, his heart pumping furiously.

"Re…mus…" Merlin whispered, words laced with pain.

Lupin's eyes grew wide as he knelt down beside him, his gaze uncertain. "Yes?" he mumbled, unsure what to do.

"Back in the… Department… of Mysteries…" Merlin managed to spit out, coughing blood and staining his shirt as he convulsed. Nobody touched him. "There's… somebody… waiting for… you."

Harry, Hermione and Ron stared, eyes as round as plates.

"Who?" Lupin asked, curiously.

Merlin inhaled shakily, gasping, "Padfoot."

Lupin's eyes bulged. "But… Pad-Padfoot d-died." He stammered.

"Yes." Merlin replied, breathless. "I know. I… I brought him… back… for you… for Harry… he's waiting… for you… both…"

Lupin looked up, stunned and then was racing away from them, back towards that dreaded door, unable to stop. Everybody watched him go.

Professor McGonagall inched forwards, her wand in her hand. "Here, let me help, I can deal with the wound –"

"No." Merlin cried out, struggling away from them, kicking helplessly. His left hand gripped Excalibur and he dragged the sword closer to his chest. "Don't come any closer." He begged them, trying to look threatening as he clutched Excalibur tightly.

"I can heal you." McGonagall whispered.

"You're m-magic won't w-work on me." Merlin stuttered. "I need the O-Old R-Religion. And I'm pretty s-sure that none of you know t-t-t-that." He hauled Excalibur up to his chest, hugging it tightly, glad that when he died, he'd at least be dying with an essence of his old best friend by his side.

"That sword." Hermione murmured, her voice quiet. "That's Excalibur."

"The one and only." Merlin tried to laugh, but only managed a strangled chuckle before his body convulsed again as the Old Religion took over once more. As soon as he was free from its grasp, he groaned. "God… Arthur's gonna kill me…" he gasped. "Well… the bloody prat never kept out of trouble either, so I guess we're square on injuries now. Eugh, what's he gonna say when I told him I might have scratched his sword…?"

Dumbledore gazed at him curiously. "My dear boy… you're not meaning to say that you…"

"That I knew King Arthur of Camelot… from… the legends…?" Merlin raised his eyebrow weakly, clutching his side with his left hand, still trying to scoot away from the group. "Yes… I did… he was the biggest dollophead ever and his ego was nearly as big as his waist…"

"Who are you?" Kingsley asked, his voice disbelieving and filled with awe. "What is your name?"

Merlin gave a few strangled gasps, breathing shallowly, his chest heaving as he sweated heavily, teeth and fists clenched with pain. He shook his head slightly, trying to fight off the darkness forcing itself into his mind. "My name…" he gasped, "Is Merlin Emrys."

He promptly passed out.