This was definitely better in my head. Oh well.
Harry was waiting for the right moment to reveal himself when a man in chainmail suddenly stumbled up to the group of wizards and witches, blonde hair and clothes dripping wet and eyes brimming with confusion.
"What the hell is going on?" he asked, taking in the destruction surrounding them.
Voldemort looked him up and down, unimpressed. "Is this some pathetic tactic to delay your inevitable defeat?"
"No?"
"I will take that as a yes."
The man scowled. "When I say no, I mean no."
Voldemort shrugged, turning to continue his speech once more. "As I was saying-"
"Why are all of you wearing black robes? Are you a cult? Is this some sort of fashion statement I wasn't aware of?" Harry was certain no man had ever sounded as confused as that one right there.
It was Voldemort's turn to scowl. "If you continue with your useless interruptions, I might just have to kill you."
That immediately put the man on guard. He took out his shining sword and held it out in front of him. "Who do you think you are?"
Shocked murmurs sounded throughout both sides. Voldemort scoffed and put a hand to his chest, trying not to appear offended. "I am Lord Voldemort, the Dark Lord, the most powerful-"
"Okay, look. I know a bad guy when I see one." Arthur gestured to all the Hogwarts students staring from the sidelines. "You're fighting children, for goodness's sake."
Professor McGonagall took this time to make herself known. "Unfortunately, these children are all we have, and they are perfectly capable of fighting on their own."
"With what? Those flimsy sticks in your hands?" he asked, referring to their wands.
Several murmurs broke out again, most along the lines of, 'Is he a muggle?'
Hermione, ever the diplomat, asked him, "What's your name, mister? I believe I recognize the crest on your cloak."
"Arthur."
"Arthur? As in King Arthur Pendragon of Camelot?"
Arthur looked miffed. "Of course! How many other Arthurs are there?" Several jaws dropped at his outburst.
Mr. Weasley raised his hand. "My name's Arthur."
The-man-who-was-apparently-King-Arthur took a moment to look at him. "Oh. Well good for you." He shuffled awkwardly at all the attention he was suddenly getting.
"Nagini, kill this one, will you?" Voldemort asked after a few moments, and cries of alarm rang out as the overgrown snake slithered towards the man.
"I'm fairly certain snakes aren't supposed to be this huge!" he exclaimed, brandishing his sword in front of him. And then, with a few maneuvers around Nagini, he swiftly cut the snake's head off.
"NO! Nagini!" Voldemort screamed.
Arthur winced as it dissipated into black wisps of smoke. "Where are we?" he asked, as if he hadn't just killed a horcrux and dangerous snake.
"We're at Hogwarts," Professor McGonagall answered, a bit wary of the man who was still dripping water.
"What is this Hogwarts? Last I checked, I was in Camelot." Harry was 50% sure the man was insane, though the dead snake was a pretty good argument in defense of his sanity.
"Hogwarts is a school for witchcraft and wizardry."
"School? School! All of you are sorcerers?! Merlin, what did you do now?!"
"Why is it always my fault?" All attention turned to the young man in muggle clothing who had certainly not been leaning against that pillar before. His black hair was wildly ruffled, and his arms were crossed in indignation.
Several gasps sounded. Voldemort just looked miffed that he was being interrupted again.
"Because it is always your fault!" Arthur replied, sounding like it was obvious.
"No it isn't."
"Yes it is."
"No it isn't."
"Yes it-"
"Look, you clotpole. You wouldn't survive a day without me. Admit it," the-man-who-was-apparently-the-Merlin said. Harry thought this was a great turn in events and hoped they'd distract the Death Eaters and Voldemort enough for their side to win.
"I won't admit it, 'cause it's not true."
"Yes it is."
"No it isn't."
"Yes it is."
"No it-"
"You don't get to argue with me about this when you've been asleep for over a thousand years!" And with that, Harry thought he recognized a bit of himself in the newcomer, a bit of hopelessness and loss and pressure to be the savior everyone thought he was.
The man in armor stepped back a little in shock. "That long? I knew - I knew I'd been asleep, but that long? Oh. Oh, god. I'm so sorry, Merlin."
Merlin stepped forward so he wasn't leaning against the pillar anymore. "It's okay. Not like you could control it or anything." He gave a wry smile, and the scene made Harry think that either these people were amazing actors to forget that they had an audience (who had previously been fighting one another), or really, really insane. He was leaning on the second option.
And apparently, Voldemort had had enough. "This is ridiculous! Do you expect me to believe that this is Merlin himself? He's so - so scrawny!"
Merlin's brows furrowed, and before he could bite back a retort, Arthur interrupted with, "So you're famous, huh?"
Merlin turned to him. "Not really, no. They think Merlin's some old sorcerer with a long, white beard."
"But that is you. Or, at least, 'Dragoon the Great'. Really Merlin, you couldn't have thought of a better name? It's a wonder you kept your magic a secret for that long."
"Well, you-"
"SILENCE!" Harry had trouble not flinching, but the two men who were definitely insane enough to face Voldemort just turned to give him similar disinterested gazes.
"We're kind of having a discussion here, so if you could-?" The-man-who-was-apparently-Merlin waved his hand vaguely, and Voldemort found that he couldn't speak, a hand coming up to his throat as if to check if his vocal cords were still there. "There, that's better."
Several shocked exclamations rose up as the man seemingly rolled his eyes. "So, these guys," he gestured to both sides, "are fighting each other because they," he pointed at the Death Eaters, "are evil. And you were woken up because the good guys needed you; fate and destiny and all that. You understand?"
Arthur nodded. "I already killed the noseless guy's evil snake."
"Oh." Merlin raised his eyebrows. "Then destiny fulfilled, I guess."
Arthur's jaw dropped. "That's it?! I was woken up just to kill a damn snake?!"
Merlin shrugged. "It has killed a bunch of people, and it was the only thing left keeping this one," he pointed to Voldemort, "alive. So, yeah. I'd say destiny fulfilled."
"That's so...anticlimactic."
"But you're also with me now, so I'd say it's worth it. It's been pretty lonely."
"Hey! I know you!" Mr. Weasley exclaimed finally. "You're the one I found smuggling information out of the Ministry the other day."
Merlin smirked. "I wasn't entirely helpless all these years."
Voldemort finally managed to get rid of the silencing spell over him. "YOU! How dare you silence me, you imbecile!"
"Oh," Merlin said, unimpressed, "I almost forgot you were there. Also," he turned towards Harry, who tried not to stiffen under his scrutiny, "you're not dead, though I do appreciate your willingness to do so, seeing as you're not a horcrux anymore."
"What? Harry!" Hagrid exclaimed, and set him down on the ground.
Harry stood up and shrugged, feeling slightly guilty at all the shocked faces of his friends. "I was counting on the element of surprise."
"YOU!" Merlin cut Voldemort off again, this time with a freezing spell.
He grimaced. "That one's an earful."
Harry, for the life of him, couldn't figure out why he laughed next. Maybe it was because this damn war was almost done. Maybe because he was just so tired. But nevertheless, he laughed, and all his friends followed.
"How dare you disrespect the Dark Lord!" Bellatrix Lestrange exclaimed at the lot of them, whipping out her wand and pointing it at the two men, who didn't look the most bit alarmed. "Avada Kedavra!"
The-man-who-was-apparently-Merlin used a hand to catch the spell in his palm. Bellatrix's eyes widened, and she stopped suddenly. Then, the-man-who-was-almost-definitely-Merlin shot it back at her. Harry almost felt bad for her as she dropped dead on the ground.
Voldemort's eyes widened.
"Look, I don't really want to kill anyone, so if all of you just leave right now and not do anything evil ever again, that's fine by me." Immediately, all the Death Eaters behind Voldemort disapparated, fleeing the scene. Voldemort also tried to do so, but was stopped by the-man-who-was-now-definitely-Merlin. "Nuh uh. Not you, Tom. You're staying right here." If looks could kill, Merlin would almost definitely be dead. Or...maybe not dead, seeing as he seemed to be immortal and all-powerful and everything. Harry didn't quite know what to make of him.
Merlin seemed to pause, cocking his head and considering Voldemort for a few seconds. "What are you gonna do with him?" King Arthur stage-whispered.
Merlin's brows furrowed, and he shushed his friend before laying his gaze back on the still-frozen Voldemort. None of them moved or talked as they watched. He sighed. "It seems I can't kill him, destiny and all that. Always hated destiny. Harry Potter has to be the one to do it."
All eyes turned to Harry, who was very, very unsure about all of this. "Uh, well. I - do I have to use the killing curse or something?" He took his wand in his hand and lifted it towards Voldemort.
"No no no. Your disarming spell will do just fine."
"Oh. Ok." A few seconds of silence.
"Well, are you gonna do it?" Merlin asked.
"Yeah, yeah. Um - expelliarmus!" And then Voldemort's skin began flaking up and it looked like he had really bad dandruff. By the time Harry put his wand down, Voldemort had completely disintegrated. Several cheers began resounding across the group.
"Well!" Merlin clapped his hands in an entirely too happy manner for someone who had just ended a war. "That's all I'm needed...probably for the next few decades or so until the next serious magical threat comes. Don't tell anyone that I was here, hmm? Actually, I don't need to ask. If you even try to do so, you'll find yourself talking about the battle in an entirely different turn of events. I've managed to destroy all documentation of my existence for centuries, and I wouldn't want to stop now."
"Wait, so. You're actually the Merlin?" Ron asked, dumbfounded.
Hermione smacked his arm. "Did you not see what he just did? Of course he is!"
"But...but. Really? That's - Merlin's beard - that's awesome."
"Hey, look," Merlin interjected, scowl in place. Ron gulped. "Does it look like I have a beard?" He pointed to his decidedly clean shaven face.
"N-no."
"Then don't say that!"
"Well...bloody hell!"
"That's better. That's so much better. Y'know, I never really understood where that came from. They couldn't have chosen something else, like 'Merlin's long hair!' or 'Merlin's ear!' or 'Merlin's left toe!' No! They had to choose beard, because that's apparently my defining factor!" He kicked the ground like...like a little kid, really. Very unlike the legend that they had all grown up with.
Arthur snickered. "They use your name as a curse? I definitely need to do that sometime."
"No you don't, you prat. You left me alone for years. The least you could do is avoid the phrase."
"I'm totally going to use that phrase."
"No, you're not. I'll give you donkey ears if you do."
"That was you!"
"Well, yes! Who else would it be?"
"You little-" And then, with a snap, they had disappeared. Harry (along with the rest of Hogwarts) gaped at the spot that they had just occupied.
And afterwards, the entire Wizarding World would learn about the Battle of Hogwarts and how Neville Longbottom had destroyed the last horcrux, how Mrs. Weasley had killed Bellatrix Lestrange in defense of her daughter, and how Harry had fought Voldemort, ultimately killing him to end the war.
Harry supposed the last bit was true, but he always wondered where Merlin and Arthur had gone, what they were doing now, and if they were happy.
Harry sure was.