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.

"Professor," Merlin greeted McGonagall, as they met in the corridor leading to where the Room of Requirement was hidden.

"Mr Ambrosius," McGonagall said, nodding. "I trust you've gained control?"

Merlin blushed slightly. "Yes. Come on, the meeting starts in half an hour…"

The warlock and the witch strode together in companionable silence until they reached the large stone wall. McGonagall frowned and then gestured to Merlin. Squeezing his eyes shut, he reached forwards with his magic and tapped on the wall.

I want to attend the DA meeting. My name is Merlin Emrys.

There was a loud whoosh as large oaken door suddenly appeared in the wall. Merlin grinned widely as McGonagall nodded, looking amazed. Shoving the door, it swung open slowly, revealing Harry, Hermione and Ron inside, cleaning up inside, placing pillows around the edges and organising books on shelves.

"Hey guys," Merlin called out, as he strode into the room.

Hermione glanced up from where she was flicking through Defying the Dark by Matthew Daley and the large heavy volume of The Wolf Within by Merida Lionheart. "Oh, hi, Merlin! We were just talking about the session plan."

"What are we doing then this evening?"

"Just simple stuff, for the younger students, and a reminder for the older," Harry said, strolling over, clutching his wand tightly. "Hermione and Ron were going to take all the students in forth-year or below and I was thinking you and I could take the older students."

"Good idea," Merlin replied, nodding approvingly.

"What spells do you think we should teach them?" Harry asked, piling books up in Hermione's arms so she could carry them to the shelf.

"Well… probably some defensive and offensive spells…" Merlin shrugged. "The stuff you used at the Ministry. Stupefy, Reducto, Incarcerous, Impedimenta… you know, that sort of stuff. This session should just be a reminder of what you taught them all last year."

Ron stood up from where he'd been placing pillows around the edge of the chamber. "Could we do Patronuses as well?" he asked hopefully.

"We did them last year," Harry explained. "But sometimes they can change, so you just need to practise them." He turned to Ron. "It's a good idea."

"It depends, how long is this session?" Merlin asked, turning to Harry.

McGonagall stepped forwards. "If the session starts at half five, I can allow the meeting to go on until half eight o'clock this evening."

"That would allow us half an hour during the session to conjure some food and have dinner," Ron said.

"Do you ever NOT think about your stomach?" Merlin laughed.

"Trust me, you get used to it," Hermione said, rolling her eyes.

Professor McGonagall began to help Hermione organise the small library with all the books on Defence at the back, while Ron set cushions about the room. Harry and Merlin expanded the room slightly and split it in half, so that Hermione could take her younger students without being interrupted by Harry's. Merlin also conjured a large piece of parchment so the members could sign their names and swear to secrecy. Merlin set it down on the table after modifying it; the parchment now had a large bold title stating Dumbledore's Army with a different magical creature in each corner; a griffin, a dragon, a phoenix and a Thestral.

At quarter past five, students began to arrive. Neville Longbottom, Luna Lovegood, Seamus Finnegan, Dean Thomas and Ginny Weasley arrived first, with Aithusa seated on Ginny's shoulder. Aithusa soared around the room once before settling on Merlin's shoulder. Terry Boot, Ernie Macmillan, Lavender Brown and Katie Bell entered, looking around, and a bunch of second and third-years arrived after them, gazing at Harry in awe. They all signed their names on the list and then filed out, chatting excitedly, as other students began to arrive in groups.

Finally, the flow of students stopped and at half five they were ready to start. There were around fifty students. McGonagall settled in a chair in the corner and began taking notes. Professor Dumbledore was nowhere to be seen.

"Right!" Harry said confidently, clapping his hands together. "There will be two groups! Hermione and Ron will be taking all students the age of fourteen or under. Merlin and I will be taking all those fifteen and over. Please separate; if you are under fifteen, follow Hermione; if you were a member last year, or are over fifteen, follow me."

The students separated, gripping their wands. The younger students, who looked very excited but also quite nervous, hovered in the corner of the room. Hermione led them behind a large red and gold curtain splitting the room; Merlin and Harry were left with the fifth-years and above.

Neville, Ginny, Ernie, Seamus, Dean, Lavender, Katie and Luna were all familiar, but there were some other new students they didn't know.

"Hi, who are you guys?" Harry asked, approaching a clump of students.

Harry immediately recognised the Slytherin girl who had slapped Malfoy. The girl had thick auburn hair and a cheeky look to her. "I'm Zana Mackay; I'm in fifth-year. I'm in Slytherin, but I'm friends with Ginny." She motioned to the two girls behind her. "This is Zoey and Lily; Lily's in Gryffindor, and Zoey's in Hufflepuff."

"Nice," Merlin said, walking over. "I'm Merlin Ambrosius, nice to meet you. And you probably know Harry."

"I'm Liam Ward," introduced a tall, grey eyed boy with messy blonde hair. "Ravenclaw."

"I'm Ryan Matthews," said another smaller brunette boy, holding out his hand. "Ravenclaw."

"Hunter Smithson," said a tall boy with ruffled dark brown hair. "I'm Gryffindor; just joined this year."

"Wow, Zana, looks like you're the only Slytherin here," Merlin said, looking surprised.

"Yeah, well, I'm decent, unlike Malfoy," Zana said, grinning.

"I like you," Harry said, laughing.

"Yeah, I can't believe you punched him," Merlin laughed. "I've always wanted to, since the moment I met him."

"It's a twice a week occurrence," Zana chuckled.

"Come on; let's get on with the lesson…" Neville whined, jumping up and down excitedly.

Merlin soon had them paired up and shouting stunning spells, shooting immobilising spells at each other and freezing one another. Harry and Merlin were both impressed by the skills they saw. The first hour passed very quickly, and soon it was time for them to eat. Merlin summoned some sandwiches and they had a picnic on the floor, sitting on the cushions, munching on crisps and drinking hot chocolate.

"I think we're ready to move on now, Harry," Merlin stated, turning to his co-teacher.

Harry nodded, grinning. "Patronuses it is."

"Okay, everybody, stand up and gather around," Merlin called out.

Everybody leapt to their feet, dashing back into the centre and forming a ring around Harry and Merlin eagerly, looking excited.

"We'll be practising Patronuses," Harry told them.

All of them started whispering excitedly, drawing their wands again in sync around the circle.

"We'll be doing it in canon," Merlin informed them, grinning. "In a battle, you want to be able to identify each person's Patronus. I presume that everybody here know's how to perform a Patronus?"

Everyone nodded mutely. Aithusa snorted, shooting Merlin a look, while the warlock turned to Harry expectantly, "So, Harry'll start…"

"Expecto Patronum!" Harry yelled. A silver stag erupted from his wand and danced around the room, tossing it's antlers.

"Expecto Patronum!" Luna shouted. A silver hare bounded about before vanishing.

"Expecto Patronum!" Zana bellowed. A large silver wolf sprung from her wand, sprinting around the room before pausing and howling.

"Expecto Patronum!" Ginny cried out. Galloping gracefully, the silver horse whinnied once before it disappeared.

"Expecto Patronum!" Katie called out. A hawk soared upwards, shrieking out a falcon cry, before exploding into light.

"Expecto Patronum!" Ryan snapped. Snarling, a silver tiger prowled, circling its caster before fading away.

"Expecto Patronum!" Liam said, waving his wand. A silver furred ermine scuttled up Liam's shoulder, blinking as it vanished.

"Expecto Patronum!" Hunter pointed his hand and a silver leopard prowled angrily.

Ten minutes later, the whole group had perfected their Patronuses and were extremely proud of each other. Harry went around the group congratulating people. Suddenly, Professor Dumbledore appeared, and it looked as if he'd been watching them the entire time. He gazed at Harry fondly before winking proudly, happy with their achievement. McGonagall was also watching, standing beside the Headmaster, looking slightly impressed.

"Hey, Merlin, you haven't shown us yours," Ginny piped up, wheeling around to face the warlock.

Merlin looked uncomfortable. "I really don't think –"

"It's only fair," Zana growled, striding forwards. "After all, if it comes to a battle with You-Know-Who, I'd rather not kill you by mistake."

Merlin rolled his eyes. "Alright then, fine!" He whipped his wand out of its sheath and pointed it into the air, though the gesture was meaningless and useless. "Expecto Patronum!"

The large silvery dragon exploded from the wand, roaring furiously, its eyes glowing, as it flew around the chamber like a beautiful eagle. Everybody watched it with wide eyes, and started when suddenly a phoenix appeared beside it, calling out its harsh cry, its silver feathers glittering. The phoenix and the dragon circled each other like friends playfully before bursting into puffs of silver light.

Dumbledore walked forwards and set a steady hand on Merlin's shoulder. "Impressive," he said, and he did sound impressed.

"Thanks," Merlin said gratefully, grinning. "Your phoenix was cool too."

"Thank you," Dumbledore said, smiling. He turned to Harry. "I'll take my leave now, Harry. Your students are in capable hands, I believe."

"Okay, I think that's the end of today's session," Merlin said, as Dumbledore vanished once more behind the curtain. "But feel free to stay until half eight to practice duelling and whatever. Just make sure nobody gets hurt."

Merlin dodged the curtain, leaving Harry to watch over the duels that were now occurring. He smiled and strode forwards to join Hermione and Ron, who were watching the younger students disarming each other using Expelliarmus.

"How did your session go?" Hermione asked curiously.

"It went great," Aithusa replied for him. "They got onto Patronuses."

"Nice," Ron said, nodding. He nodded towards his students. "This lot can't even perform a proper jinx, it's going to take ages before they're ready for the Patronuses."

"On Saturday you can take the older lot with Harry," Merlin told him. "I don't mind teaching the younger students with Hermione. It will be fun."

"Nah, it's okay," Ron replied. Merlin frowned at the sudden hardness of his voice. Did Ron… did Ron like Hermione?

Hermione and Ron once again took control when a first-year accidentally gave a third-year a cat tail. The session ended on a high when Seamus and Neville had to separate Liam and Ryan's arms from each other (A misfired connection spell). McGonagall helped clear up at the end, flicking her wand to pile up cushions and books in the corner.

"When is the next session, Potter?" McGonagall asked, as they exited the Room of Requirement and the professor escorted them to Gryffindor Tower.

"Saturday," Harry replied. "I was thinking that we could schedule each group at different times; the younger students in the morning, from nine to twelve and then the older members from two to five."

"That will allow all four of us to work with each group," Merlin said, nodding. "Then we could do each Monday night as well, from half five to half eight. And if you want, on Thursday evenings I can take a private session for the DA members wanting to be in the Order; you know, Neville and Luna, Ginny and you guys."

"Good idea," Ron praised. "What would you teach us?"

Merlin hesitated. "I was thinking of teaching you about the Old Religion. It helps you understand spell law and condition."

McGonagall paused outside Merlin's door, lighting the tip of her wand. "If you wouldn't mind, could I invite a few other teachers to the Thursday session? The Old Religion would very much help us with our understanding of magic."

"Sure," Merlin said, sounding surprised. "Of course."

Merlin nodded, smiling, before slipping through his door into the Pendragon suite, vanishing from sight, Aithusa resting on his shoulder. McGonagall led the remaining trio to the Gryffindor tower before retiring herself. Harry was exhausted so went up to bed immediately, with Ron following behind him. Hermione was forced to stay up later until almost midnight to finish her work.

Midnight came and went. Merlin sat on the edge of his bed, clenching and unclenching his hands, experimenting with this New Magic, frowning when he found that it could be made to fuse with the Old if need be. Maybe… maybe he could teach Harry how to use Old Magic.

Harry using Old Magic against the Dark Lord, with Merlin by his side, was a beautiful thought. Merlin drifted off to sleep smiling that night.