As several of the other students secured the polyjuiced death eater, Harry brought Neville up to speed on their plans. When Harry had finished, Neville chuckled to himself and shook his head.

"Alright, let me see if I have this right. You need to find two pieces of You-Know-Who's soul, destroy them, and then fight him yourself? And you're planning to lure him to the school to do it?"

Harry nodded. "Yeah, that's about the size of it."

"It's never easy with you, is it?" Neville said with a sigh. "Alright, what can we do?"

Harry blinked at him. "I don't…"

Neville did not give him time to gather his thoughts. "Some of us have been here in hiding since Yule, Harry. We didn't keep the DA going for fun. We're the resistance." He gestured at the younger students, watching their conversation from around the room. "Some of these kids are alive because we got them to safety before the Carrows could go too far."

There was a hard edge to Neville's voice. It forced Harry to think about what life in the castle must have been like for those who remained. Being taught, and tortured, by death eaters on a daily basis, for example. Several had already mentioned how they had been prevented from going to the infirmary, so that their wounds and scars would be reminders of their 'proper place'.

He looked across the faces of his friends. Ginny, Seamus, Neville, dozens of others. Even those who looked weariest clearly wanted to help in the battle to come.

"Alright," Harry said, nodding to them. "We need to secure the other six death eaters first."

"The Room will open doors near their locations, if we know where they are," said Neville. "We'll just have to stun them before they can fight back." He paused, glancing over at Karn. "Unless your friend can help?"

Harry turned his eyes to the silver golem, who had again placed a hand on the stone wall of the Room of Requirement. Karn had suggested that he could locate anyone in the castle, using the magic of Hogwarts itself. Perhaps some of his other talents would work here, as well.

"Can we cancel the polyjuice, I wonder?" Harry asked, looking over at the bound death eater. Five of the older students were watching over their captive, wands at the ready.

"No need," said Karn, from his place by the wall. "There are three in a room near the entrance hall, two in a classroom with students, and one in the Headmaster's office."

"Snape," Harry spat. "I'll handle him."

Karn tilted his head, his yellow eyes meeting Harry's. "I should like to meet this Headmaster Snape, Harry."

Harry nodded with a grin, his wand in hand. "Well then, let's not keep the man waiting."

oOoOoOoOo

Daphne Greengrass sat in her seat, patiently waiting for the other shoe to drop.

Dark Arts class, as it was now known, was taught by Professors Alecto and Amycus Carrow. Taught, of course, was not entirely accurate, for as much glee as the Carrows took in forcing students to curse each other, they did very little actual instruction. Assignments were almost always practicals, conducted during class.

Failure to participate was… unwise.

As the year had dragged on, however, even the Carrows just stopped caring. Here they were, ten minutes into the class period, and they had not even interrupted their whispered conversation to give the students instruction.

Daphne was not worried about her NEWTS, of course, because she was a pureblooded witch. As long as she signed her name correctly, she'd get at least an E. Such was the way of things under the new order.

She looked up at the ceiling, knowing that she could not get away with napping - but finding herself tempted all the same.

A red light caught her eye. The glow was directly above the professors, both of whom were oblivious to it. As she watched, the light grew into a ring. After a moment, four wands stuck out of the ring, each aimed at a Carrow.

Stunners rained down, and both professors slumped to the floor. Students screamed, and frantically backed away. The ring widened again, and four wizards dropped down to the floor.

Two of Daphne's housemates recognized the intruders, and fired bone breakers. Both were stopped by shields, followed closely by more stunners.

The remaining students were against the far wall now, most having forgotten that the Carrows routinely kept the classroom door locked.

"I owe you a galleon, mate," one of the intruders said, his Irish accent catching Daphne's ears. She turned, and took a closer look at their attackers. The one who had spoken was a Gryffindor, she realized. Sean? No, Seamus.

Bloody hell, she thought. They're all Gryffindors.

"Two looked simpler on parchment, Seamus," replied Neville Longbottom. "Good thing we took the three guards down first." He aimed his wand at the ceiling, and let loose with a cannon blast charm. The room quieted, as all eyes turned to the missing lion.

"Right," Neville began. "Anyone else want to join the Carrows? We'll wake you up when it's all over."

No one moved.

After a moment, Neville nodded. "Good. In a few minutes, you'll be summoned to the Great Hall. Until then, sit back and relax. Thank you." He looked up at the ceiling, and the red portal still visible there. "Go ahead, Harry!"

The red light disappeared from the ceiling, only to reappear underneath the two death eaters and their two sympathisers. To the shock of the class, each of the four was dragged through, disappearing entirely. Then, the red portals disappeared. A fifth ring appeared on a side wall, and the lions walked casually towards it.

"Longbottom!" Daphne shouted.

Neville turned, an eyebrow raised at her.

Daphne eyed her classmates nervously, before looking back to Neville. "Good luck," she said quietly.

Neville winked at her, before he walked nonchalantly through the wall.

oOoOoOoOo

The wards of Hogwarts had been acting erratically all afternoon. Severus Snape, Headmaster of Hogwarts, had gone to his office to research the matter. If the signals he was getting meant what he thought, then today would be the day he had dreaded for seventeen years.

The end could not come soon enough for the Potions Master.

And so, Snape stood in his office, a glass of scotch in his hand, looking out over the grounds of Hogwarts. He did not hear the portal form against the far wall, nor did he hear the silenced footsteps of a wizard and a golem.

His own wards told him when he was no longer alone in the office, but still he did not turn.

Harry Potter could only keep his silence for so long, though.

"How dare you," Harry hissed, angrily. "How dare you stand where he stood."

"If you intend to slay me, Mister Potter," Snape replied, disdainfully, "Then have at."

"Your fate remains to be decided, Headmaster," came a deep, unfamiliar voice.

Snape turned, and saw Harry Potter standing there, his wand in hand, as if the boy was trying to talk himself into throwing a curse. It was the creature next to him that drew Snape's attention, with its unfathomable yellow eyes.

"What is this?" Snape asked.

Harry inclined his head. "This is Karn. He is helping us end the war."

Snape's features drew themselves into a sneer, despite his uncertainty. "Just as arrogant as ever, Mister Potter, I see? You plan to end an entire war by yourself?"

"Perhaps I misunderstand your language, Headmaster," Karn replied, his calm voice never wavering. "When exactly has Harry Potter been alone?"

Snape scowled, but said nothing.

"Even after his death, I am told that your predecessor offered his guidance, setting Harry and his allies on the path to this confrontation. Is that not so?" Karn shifted, considering Snape's reaction. "You know of his task, then."

Snape's eyes darted to the scar on Harry's head, that famous lightning bolt scar. It was the briefest glance. But it was enough.

"Yes, I see that you do," Karn continued.

A chill ran through Snape. "You know what he must do, then." It was not a question.

"I know no such thing, Severus Snape," Karn said. His voice kept its calm tone, but that just made the admonishment worse, for all of that. "Do you really think that your world is the only one to have dealt with Soul Jars before?"

"Your world?" Snape repeated, absently. "What are you?"

"I am the Heart of the Legacy, the Last Vestige of the Tolarian Academy, and the Soul of the Weatherlight." Karn stepped forward as he spoke. As before, his voice never wavered, which unnerved Snape all the more. "I am the Great Creator, the Silversmith, the Artificer. I have walked across the centuries, stepping from world to world as you step from room to room."

"But most importantly," Karn said, gesturing at Harry Potter. "I am his ally in his battle against your so-called Dark Lord."

However Dumbledore had expected this moment to play out, Snape was certain that this was not it. But his last instructions were clear.

"The boy must die by the Dark Lord's hand, or all is lost!" Snape snarled. "If you know what he carries, then you know what must be done. It is the only way."

"In your world, perhaps," Karn conceded. His yellow eyes grew bright as he continued. "When the moment arrives, I will take care of Mister Potter myself."

oOoOoOoOo

"I have always been intrigued by the Goblins, Lucius," Voldemort said calmly.

Lucius Malfoy glanced around his home, seeing the dozen armored goblins strewn about the floor - or, rather, what remained of them. The thirteenth, an emissary from Gringotts, was floating in the air, clawing at his throat in hopes of choking down one last breath.

"Yes," the Dark Lord continued. "They make such exquisite noises as they die." His wand twisted, and the goblin's chest seemed to burst open. Bone and flesh sprayed across the room, as the goblin seemed to fold backwards. As he finally dropped to the ground with a wet thud, Lucius could see that the creature was still moving, though even that ceased after a few moments.

Voldemort was now speaking with Nagini, hissing back and forth in a way that never failed to send shivers down Lucius' spine.

"I agree," Voldemort said, after a minute. "We must go to Hogwarts." He looked to Lucius. "Summon our forces."

Malfoy bowed, as was proper. "Which of them do you desire, My Lord?"

Voldemort turned his red eyes on his erstwhile host. His smile was sinister, even more so than usual.

"Why, all of them, of course."

oOoOoOoOo

Snape and Karn turned at Harry's hiss of pain. Moments later, Snape grunted in pain of his own, as his dark mark began to burn.

"He is coming," Snape said.

"As expected," Karn replied. He turned back to Harry. "The Goblins, then?"

Harry nodded, his hand on his scar. "You were right, they went straight to him."

Snape looked from one to the other. "There are five other death eaters in the school," he began.

"Six," corrected Karn. "All have been dealt with."

Snape paled. "Dealt with?"

Karn turned his eyes to the Headmaster. "There are many who would not hesitate to take a life. I am not among them."

"We captured them," added Harry. "They will remain bound and unconscious until the battle ends, one way or the other."

Snape nodded, not sure what else to say. "And what of me? He will expect me to open the gates to him."

Karn and Harry shared a look. The golem turned to a shelf, and began fashioning one of Dumbledore's old knick-knacks into a small, polished metal disc. Harry, meanwhile, looked back at his old potions professor, and grinned, knowing the man could do nothing about it. Not anymore.

"Headmaster," he said, using Snape's title for the first time. "Who do you have as a Deputy?"

oOoOoOoOo

The students of Hogwarts were assembled in the Great Hall, their prefects keeping them in place and quiet. No one knew what was happening, except for one group of Seventh years who had just come from their Dark Arts class.

A few of the Slytherins noticed their prefects were missing, along with several of their older students. But none of the professors seemed willing to answer questions, and so they kept silent.

Presently, Headmaster Snape entered the hall, his black robes billowing behind him, as always. He spoke in his usual drawl, giving no hint as to the situation.

"I have learned that Harry Potter is somewhere in the castle."

Whispers filled the room at the news, until Snape reached the end of the hall and turned around.

"Anyone who knows his whereabouts should speak now." His eyes roamed across the students, most of whom kept their heads down to avoid his gaze.

"He took our professors!" one girl shouted. Snape whirled about, his eyes narrowing when he recognized the informant.

"Miss Parkinson, please step to the front of the hall." He turned to look at the rest of the students. "Anyone else?"

When no one else volunteered, he nodded to Professor Flitwick, who escorted Pansy out a side door. No one in the hall saw the stunning spell that knocked her out.

"Very well, then," Snape intoned. "The rest of you will remain here, until the Dark Lord arrives." He ignored the fearful whispering, and continued. "If you will not reveal the traitor to me, then perhaps he will be more… persuasive."

Several of the Gryffindors looked to Professor McGonagall, who already had her wand out. Snape saw their glances, and sneered.

"Do you object, Deputy Headmistress?" he asked, not turning to face her.

"Aye," she said, her highland accent thick in her anger. "I do." And then her wand was in motion.

Snape barely shielded himself, turning as he did so. He did not fire back, however.

"I should have expected that," he snarled. "Come then, Minerva, let's give them a show."

McGonagall responded with a series of three curses. The first two were blocked, but the third managed to knock Snape down. His wand clattered on the stone floor of the Great Hall, well out of his reach. McGonagall was on him in moments.

"Your services, Headmaster, are no longer required." She glared at him a moment, before aiming her wand at the fallen death eater. "Incendio"

A burst of flame leapt from her wand, consuming the Headmaster in a flash. When the students looked back, they saw only a small pile of ash.

Remarkably, no one cheered the demise of the Headmaster.

oOoOoOoOo

After sending the students to their common rooms, and arranging the older years to defend them, Minerva McGonagall went to the Headmaster's office. The gargoyle opened for her without prompting, which gave her pause. Then she heard the voices from the top of the stairs, and made her way to the office.

Inside, she found Harry Potter, a large silver suit of armor, and - to her great relief - Severus Snape. She walked to the desk, and handed a small silver disc back to her (former?) boss.

"An impressive set of illusions, Severus," she said, before frowning. "Was it truly necessary to do that in front of the children?"

Snape said nothing. Instead, he nodded to the suit of armor.

Yellow eyes turned to face her, and she felt some of the ancient power within the creature. For there was no doubt in her mind that the being in front of her was alive, not with eyes like that.

"Professor Snape's true allegiance must remain hidden," the being said, speaking in a deep, otherworldly voice. "If the battle turns as it might, he will have a freedom of action he would lack if he openly stood beside or against the Dark Lord."

McGonagall nodded. "Then you have a plan."

"We do," replied Harry. "We will need to fortify the wards, while Karn here delays the death eaters."

Karn noticed the Deputy Headmistress' confusion, and nodded to her. "Greetings, Minerva McGonagall. I am known as Karn."

She stared at him, blinking. "A pleasure, I think."

Harry chuckled at that. "Who do you think designed that illusion? Karn is a master artificer, and after seeing his work, I'm inclined to agree."

McGonagall looked up at the golem, trying and failing to figure out exactly what he was. Then she decided that it really didn't matter, not right now. But she did have a question for him.

"Well then, Karn," she said. "What do you have planned for your next trick?"

"That will depend, Professor," he replied. "Do you, by any chance, have 820 pounds of silver?"

McGonagall paled. "The castle's elves might be able to come up with that, and I stress might, but whatever for?"

Harry shared a look with Karn. "We'll never be able to defend the castle without help. So we're summoning all the help we can."

"Yes, but… Mister Potter, that is quite a bit of silver. Just who do you expect to summon with that, exactly?"

"Professor," Karn said solemnly. "Perhaps it would be best if we preserved the surprise."

McGonagall scowled, but nodded. "Very well, I will trust you, Mister Potter."

"Yes, Ma'am," Harry said, with a grin. Then he turned to Snape. "By any chance, sir, do you know the weight tolerance of the Eastern Tower?"

"Why in Merlin's name would you need to know that?" Snape sputtered.

Karn told them.

oOoOoOoOo

Voldemort stood with his inner circle, overlooking the grounds of Hogwarts. Already, he could see the shimmering dome of magic that marked the wards protecting the castle.

"They were warned," he muttered to himself.

"Snape has yet to arrive, My Lord," said Rodolphus Lestrange.

"No, I suspect he has betrayed us," Voldemort replied. "Pity, that."

Augustus Rookwood, a former unspeakable from the Department of Mysteries, was peering at the castle through a small telescope. "What the hell did they do to the East Tower?"

"It looks like metal," Pius Thicknesse answered, squinting at the shining disc mounted on one side of the tallest tower.

As they watched, the disc began to glow with a purple light. Clouds began to circle over the tower, almost as if they were caught in some sort of vortex. The purple light grew in intensity, forcing most of the death eaters to shield their eyes.

The ground rumbled beneath them, almost as if they felt the shockwave from a massive spell. Then, the ground rumbled again, just as they heard a dragon's roar.

As one, the Dark Lord and his followers turned their eyes to the castle, only to see the source of that roar - a dragon none of them had ever imagined in their wildest nightmares.

The creature seemed to dwarf the castle as it stretched up, standing on its hind legs. Its wings stretched out, glowing red as they blocked out the sunset. Atop its serpentine neck was a comparatively small head, crowned by two enormous horns. The horns seemed to crackle with magical power, the energy visible even from this distance.

As they watched, an orb of power formed between the horns. It seemed to bleed malevolence, and the death eaters - none of them strangers to the darker sides of magic - felt it as if it were a physical attack.

Voldemort did not notice the reactions around him. His focus was on the eyes of the beast - those ancient eyes, and the sheer hatred he felt from them. He did not react until he heard the beast's next roar. To the Dark Lord's shock, he understood the creature.

Somehow, this beast spoke parseltongue.

After a moment, what the creature had actually said sank in, and Voldemort snarled with fury of his own.

"Come to me, Half Blood coward!" the dragon had shouted. "Come, meet your death! See for yourself the fate of all who challenge Nicol Bolas!"


A/N: Juggling multiple ongoing stories, even ones intended to be only a few chapters, is more challenging than one might expect. I realize, as I look through my ongoings, that I have neglected Karn, and so here we are.

Karn's command of magic, coupled with literal millenia of knowledge, means that his powers boil down to "Whatever badassery is required for the plot." I've narrowed his focus to illusions, artifacts (including the classic ornithopter, seen next chapter), and portals. He, of course, has other tricks, as we'll see. Part of me wishes that I started this crossover earlier in the HP canon, so that Karn and Dumbledore could have had a conversation. However much you credit (or fault) Dumbledore for his pacifism, you have to admit that Karn took it to a whole new level.

Suffice to say, taking a pacifist into a war is... well, not exactly what I expected when I wrote chapter one, that's for certain.

Karn's quote to Snape about the captured DE's is an adaptation of his quote from the Steel Golem card, from the Weatherlight set (which dates me, I know). The original quote went as follows: "Although I would give my life to protect Gerrard, my conscience will not let me take another's. There are many who would not hesitate. -Karn, silver golem" In this context, I believe the sentiment works.

If you're in the US, have a plan to vote. Then actually vote. Bloody hell, don't forget the important part!

Feedback, as always, is welcome.