Hi! Thanks for checking out my story. A few things you should know:

1. This will contain Merlin/Arthur. Not anything graphic - that's not my style - but definite romantic undertones. Their relationship and what it meant to Merlin is a big part of this story.

2. Yes, I no people can't apparate to Hogwarts, but Merlin is not most people.

Other than that, there's not much to say. Enjoy!

Chapter 1

Merlin hadn't visited this lake in twenty years.

It was a beautiful sight, as always. The water was utterly calm, disturbed only occasionally by a leaping fish or a bird that swept over from above. It glittered, light from the sun bouncing off the waves, giving it an ethereal sheen.

Twenty whole years. It would've seemed to like a long time to any other person, but to Merlin, it was a mere minute - a second, even - compared to how long he'd been in this world.

Nevertheless, he couldn't help the prickle of guilt that poked at him. He felt a sort of obligation to visit Avalon every once in awhile. As silly as it may seem, he wanted to, in his own, strange way, keep Arthur company.

Merlin smirked at the thought - Arthur would hate that kind of thing. Don't be such a girl, Merlin, he would say in that obnoxious voice. I don't need anyone to keep me company, much less the likes of you.

He missed that. The back-and-forth. The sarcastic comments and the jibes and the fond smiles just for him and-

Merlin took a deep breath and shook his head. He couldn't let himself linger on that. He'd succeeded at dealing with his feelings for the past one thousand years. He wasn't about to let that dark, seemingly inescapable sadness come back.

He'd barely managed to crawl out of that hole. He had no intention of falling back in. Not ever.

Getting to his feet, Merlin let his eyes drift over the lake one last time, a smile appearing on his lips as the brief feeling of sorrow faded away. Those moments had gotten rarer and rarer as the years passed by. They'd almost disappeared altogether.

And besides - Arthur would return one day. Kilgharrah had assured him of that. He wasn't about to give up hope now. Not when he'd been holding onto it for so long.

After gazing at the lake for a few more seconds, Merlin turned away, closed his eyes, and whispered, "Brýdhlóp."

When he opened them, he was greeted with the familiar sight of his house. It was a simple flat - one floor, one bedroom, a small living room and kitchen. It was rather outdated, as well, though that was to be expected. The walls were hardwood, as was the floor, and the furniture was small and, at times, itchy.

But it was home. It had been for the past sixty years or so. It was located in the English county Nottinghamshire, a lovely area with rolling hills and yellow fields and gorgeous green forests. The people were nice as well - excluding a farmer who lived a few miles down the road. He was quite nasty, especially during the harvest season.

Merlin looked over at the clock and grimaced. He was going to be late! He quickly hurried over to his suitcase and grabbed ahold of it, before making sure all the doors were locked. It may not have looked it, but the house held a great deal of valuables, including priceless volumes scholars had spent centuries looking for.

He paused to look in the mirror. His jet-black robes were a tad bit short for him - you could see an inch or so of his socks - but they would do. His hair was rather untidy, but nothing society wouldn't accept with more than a short, distasteful look.

He grinned, excited for the first time in ten years. He loved Hogwarts - after all, he'd helped create it, in his white-bearded disguise. A good thing, too, or he might've otherwise been recognized.

Albus had owled him about a month ago, asking if he'd be interested in a teaching position. He'd apparated - yes, he'd taken to the modern term - to Albus's home immediately, with a flow of "yes's" spilling from his lips. He'd been more than willing.

Of course, Merlin knew why Albus had asked, and it wasn't to save him from boredom.

Harry Potter.

The saviour of the wizarding world was coming to Hogwarts this year, and Albus wanted Merlin's help to counsel the boy. "In case Voldemort does return," his old friend had said, "He needs to be ready."

Merlin scowled at the thought of the so-called Dark Lord. He'd been ready to face off with the man himself, but had been halted by a vision from the Old Religion.

Defeating Voldemort was not his destiny, it told him. Harry Potter alone could destroy him.

He should have been thrilled - for once, something wasn't his destiny - but it had been torturous to let that lunatic rage throughout Europe, killing innocents and spreading his disgusting ideology. He'd been beyond relieved when he was finally defeated.

Until he'd learned the truth from Albus. Learned that Voldemort might return - in fact, probably would - and when he did, Merlin would once more have to remain idle and let Harry Potter take down the dark wizard.

And so, when Albus told Merlin what his reasons for hiring him were, he'd been even more determined. If he couldn't fight Voldemort himself, he'd do his best to assist the boy who could.

And after all, helping the hero was something he was rather famous for.

Taking a deep breath, Merlin closed his eyes once again and spoke in the language of the Old Religion.

And, upon opening them, found himself on the bank of the Black Lake, in front of a looming, enormous, magnificent castle.

Hogwarts.

Grinning, Merlin walked up to the large wooden doors and knocked three times. A few moments later, they swung open, revealing an open room, a long, stone staircase, and a stern-looking woman wearing a pointy hat.

"Ah," she said, eyeing Merlin curiously. "You must be Professor Marius Emrys."

Merlin giggled inwardly - Professor - and gave the woman a friendly smile. "That would be me!" he chirped. "And you must be Professor McGonagall. Albus has told me all about you. He sings your praises, truly."

Professor McGonagall continued to regard him warily, but said nevertheless, "Please, call me Minerva. I'll show you to your room."

"Thank you very much, Minerva," Merlin replied, following the witch as she led him up the staircase and to the right.

After a few minutes or rather confusing twists and turns, she stopped in front of a portrait of a - well, what were the odds?

It was him.

Not moving, obviously, given he was still alive. But it was nicely painted nonetheless. A bit old, as it depicted his famously bearded self, but still nice.

Merlin smirked. Albus clearly loved his jokes.

"The password is Avalon -" Imagine that, Merlin thought, "- and, as far as I know, stays constant throughout the year. I hope it's to your liking."

"I'm sure I'll love it," Merlin replied, smiling. "Everything in this castle is so beautiful."

At Minerva's raised eyebrow, he quickly backtracked. "From what I've seen," he said hurriedly. "It's very, erm, very nice. From..what I've seen."

She certainly didn't buy it - she seemed far too clever a woman to believe him - but she let it slide. "You have about twenty minutes until the start of the ceremony. I'll send someone to show you the way."

Merlin grinned. "Thank you, Minerva. I'll see you then."

Minerva gave him a tight smile in return before heading off back down the staircase, shoes clicking on the stone floor.

Shaking his head - how, after all these years, did he manage to slip up? - Merlin turned to the portrait and said, "Avalon."

The painting swung inwards, and Merlin climbed through the hole, gripping his suitcase tightly.

It was a lovely room. Not that he was all that surprised; like he'd very stupidly just said, Hogwarts was a truly beautiful place. Even the dungeons had a strange sort of gothic appeal.

His quarters were small, but quaint. The walls were a deep blue color, and covered with various paintings. There was a tiny common room, an even smaller kitchen, and two doors down on a hallway to the right - the bathroom and bedroom, he assumed.

The fireplace was empty, so Merlin lit it with a mere glance. Fires had been easy for centuries.

He probably should have lit it with his wand, but the wooden stick was just so...boring. He understood the necessity - modern sorcerers were unable to channel magic directly - but they still irritated him. Forcing magic through such a small outlet wasn't hard, but it felt rather hollow. He much preferred traditional means.

Of course, traditional means had their drawbacks. Mainly, his eyes. They still glowed molten gold each time he performed magic without a wand. This was something witches and wizards had been unable to do for ages. He had to be careful about his methods of using magic, lest he be caught by a student or fellow teacher.

Merlin made his way into his room, making the fireplace within light up as he had with the first one. It was also rather small, but had a comfy feel to it. Beside the bed was a small desk, as well as a cupboard for his clothing. Tossing his suitcase onto the bed, he began to unpack. He could've used his magic, of course, but he had time to kill. So, he went about the process more slowly than usual, waiting for a knock on the portrait door.

As Minerva had promised, it came about fifteen minutes later. Merlin sat up from where he'd been lying on the bed and hurried to the entrance, excitement beginning to bubble up inside his chest. He couldn't wait to meet more sorcerers. Besides Albus, he wasn't really on friendly terms with any of them, and was rather looking forward to changing that.

He stopped to straighten down his robes, as well as his hair, before stepping through the portrait hole to meet his escort.

A tall man who stood before him. He gazed on Merlin with dark brown - almost black - eyes, through a curtain of greasy hair. His face was more or less expressionless, though Merlin couldn't help but notice a hint of vague hostility in the man's eyes. "Professor Emrys, I assume?" he asked in a bored, drawling voice.

Merlin nodded. Refusing to be put off by the man's strange aura, he smiled politely. "That's me!" he said cheerfully.

He stood for a moment, waiting for the man to offer his own name.

He said nothing.

Merlin coughed awkwardly. "And who might you be?"

The man was silent for a few moments, eyes assessing Merlin, before responding, "Professor Severus Snape. If you'd follow me, please."

And he was off, black robes sweeping behind him as he strode down the hallways, not bothering to look back.

Surprised, Merlin quickly followed, nearly jogging to keep up with the Professor's wide long stride.

"What subject do you teach?" Merlin asked curiously. Perhaps the man was just a bit guarded. A little conversation might open him up.

"Potions," Snape replied sharply.

Merlin waited to see if he would elaborate, but the wizard remained silent.

"That must be an interesting subject," Merlin said. "Personally, I've never cared much for it-"

"Shocking," Snape interrupted, voice lightly coated with disgust.

Merlin paused. Wow. Someone has a chip on his shoulder. But he'd dealt with his fair share of bitter people. He knew how they ticked. It wasn't easy to get through to them, but he'd had a lot of practice. Prince Charles had been a particularly nasty one, but he'd grown to trust Merlin eventually.

The key was to not push. So, Merlin just said, "Well, I'm sure you're brilliant at it. Maybe I'll learn some while I'm here," and then turned away from the professor, keeping his eyes fixed ahead.

When they reached the enormous double doors that led into the Great Hall, Merlin looked at Snape and said kindly, "Thank you for showing me the way, Professor. I appreciate it."

Snape didn't say anything - just nodded curtly.

A moment later, the doors opened.

Merlin grinned. For the first time in five hundred years, he was back at Hogwarts.

This was going to be fun.

So, what did you think? Let me know in a review! :D