Doom Days (Harry Potter/MCU Crossover)

Pre-Chapter A/N: More chapters on my patreon(https://www.patreon.com/c/Oghenevwogaga)— same username as here and link in bio. Experimenting with two chapters a week, we'll see how long I can keep this up for. 

It was a chess game, I realized when I walked closer and leaned over it. The pieces were not clearly demarcated. Instead, they were the same dozens used for each piece, but the board was definitely a chessboard, and the position that was presently upon it was one that was easily reachable in a chess game. In fact, it was move seven of the mainline theory of the London System. How ironic. I only knew so much chess theory because Tom Riddle had seen chess as one more way to lord his intellect over the Muggles that had been bullying him for his short existence, and he made sure to get so good that none of them would ever have a fighting chance of beating him. 

That meant I knew what the next move was supposed to be, and I made it. I made the next one when the other color moved as well. We continued like that for the next seven moves until the puzzle decided that I had had enough before it began to click to open, and that was when I was interrupted, poetically enough. 

"Vicero" I bent over backward to dodge the surprisingly dark curse from my Hufflepuff competitor. 

"I don't think Sprout would be much too pleased to see you casting magic like that." Instead of replying, he scowled and sent another spell flying my way. When I had to split my attention between him, Fleur, and Krum, there had been the makings of a fight there. Sure, I was far from being truly challenged, but I hadn't just been able to steamroll them. Without the others though, "steamroll" was too kind a word for what I did to Diggory. He put up his best for the few seconds he managed to last. He truly did. But what did it matter when that best ended with him disarmed and bound with chains cursed to tighten against his skin further the more he struggled? 

If only that was the end of it, I thought, as I was harassed by a flock of birds that seemed to appear out of nowhere and begin pecking at me. A Disillusionment Charm on the birds themselves until they were in range? Fleur! I twisted my wand, setting the birds on fire with one blow, and then twisted my wand around my head, casting the wide-area Hominem Revelio. Fleur's glowing hand was mere inches away from the cup. She blocked my bludgeoner, but the force of it was enough to force her at least a step back even as I felt my heartbeat accelerate at the almost defeat. She retaliated with a series of hexes. Each one flowing from the others. None of them even remotely dark, but all of them annoying as hell. 

A Knee-Reversal Hex was not likely to do irreparable damage on its own, but taking a spell like that would fuck up my mobility and could mean the end of this duel. "Argh," I said in annoyance as I shattered the steps beneath me with a blasting curse. The stones I turned into massive snakes that I banished in her direction. 

"Bind, do not bite," I ordered them in Parseltongue, taking note of the way she shivered at the magical language. Few people could just shrug off hearing it for the first time. She ignored the snakes for as long as she should, keeping up her constant rain of hexes and jinxes. Each spell she sent was cast perfectly and clearly chosen for how easy they were to cast, and thus how quickly she could use them in a duel. Of course, ignoring the snakes meant that it was only a matter of time until she would be out of the fight as they crossed the distance and began to reach her feet. She turned to deal with them, and my bludgeoner caught her right in the midsection, sending her flying off the stairs and into the maze's wall a second later. 

The cup was here, right here, and it was mine. The others were out of the fight. Fleur's wand had flown from her grip, and Cedric was moaning in pain while the chains ran their course. Krum? We'd lost him much earlier. This was it. It was my win. Then why did it feel so empty? It felt like I had come first in a race, but one where I had been the only one running. There had been nothing competitive about this, and it showed. I'd dispatched the two of them in no time at all. Fleur had been getting better all year, but she could not even still compete on even footing with the version of me that had faced the Hellhound. Maybe she would have given him a fight, but not too much of a struggle. I leaned forward and grabbed the cup by its base, closing my eyes and taking a breath as I did so. 

This time, when I felt the hook-about-my-navel feeling, I did not struggle against it. I just allowed it to take me. That was why I froze for a second when the portkey ran its course and I could not hear any of the crowd's shouting or cheering. In fact, it was dead silent. I opened my eyes and found myself in the middle of pandemonium. Pandemonium that I was shielded from by a bright golden dome that surrounded the podium I found myself atop. The stands were clearing out as students ran for the castle. Half of one set of the stands was just gone. Gone completely, with only the accompanying half that remained being a testament that it had ever been there. 

Dumbledore stood in the middle of the chaos like a conductor, weaving his magic and fighting close to a dozen cloaked figures at once. 

"Harry Potter," I heard a whisper and turned around to find a man standing outside the dome I was contained in. How had his voice penetrated when it seemed sound couldn't get in? 

"I have been paid a very handsome sum for your retrieval. While I usually would prefer more direct means, I have seen enough of your strength at arms to not want to fall afoul of you in a duel. Instead, this will be my tool. This doom you are within. Nothing goes in or out unless I will it. Sound, people, magic, oxygen…" He read the list off with what I was sure was a smirk. He was wearing a hood, and where his face should have been was just a mass of darkness. 

"Avada Kedavra!" I said instead, aimed right at him. The spell hit the dome, the dome rippled, and glowed even brighter. 

"A worthy attempt, but any and all magic gets broken down before it hits the dome itself and works to strengthen it. And in case you are wondering, your own magic is also working to strengthen the dome. I wonder which would overcome you first, magical exhaustion or oxygen deprivation?" he said, taking a step back, and turning away from me. 

I looked at it, really looked at it. Yes, the thing had gotten brighter since I sent the Killing Curse, but it was also getting brighter regardless. It took me the same amount of time to conclude that yes, there was no new air coming into the dome, so I would keep recycling the air over and over again until I ran out. At least for the second there was a solution. With a twist of my wand, I cast a Bubble-Head Charm. The charm had the natural ability to filter and reuse oxygen even in places where there was none. Don't ask me how, it's just classic magic bullshit. 

The bubble formed over my head and I took a healthy deep breath of the fresh air, enjoying that that problem was solved before it could ever be one. Except that I began to watch the bubble fade. It faded and faded second after second until with a pop it was gone. What the fuck. The dome was absorbing magic, of course. Even a non-combat spell like that one had been absorbed as well? Fuck. 

So that went that plan. Oxygen was still going to be a problem it seemed, but the more pressing one was magic. I hadn't been running at full when I got here. I'd gone through the entire third task, and then there were the duels with the other champions, the time spent fighting Peeves, the Boggarts, the Acromantulas, the dozen silly things in the maze. I'd had a day and then some. So the fact that I was beginning to feel a bone-deep tiredness after just a few minutes in this dome meant something. 

I looked over at Dumbledore, and I could see the situation more clearly now. Some of the students had been herded away from the others and were being used as hostages. It meant Dumbledore could not fight at full strength, and the rest of the Professors were stuck trying to attempt rescue missions. Even Sirius was visible from here—he was fighting two cloaked figures at once, and they were the ones struggling to keep him at bay. 

"Sirius!" I shouted, trying to get his attention. He managed to nail one with a jinx that forced him to punch out his partner before stunning them both. He looked around, even turning in my direction for a brief moment, but instead of seeing me, he seemed to look past me before he settled on his next target. 

Fuck. Of course, they'd used some sort of Notice-Me-Not or cloaking enchantment. The billboard that was supposed to display the Champions' progress had gone black. No one had any idea I was here, and once this distraction ran its course, they were going to leave with me with none the wiser. It was a good plan. Fuck it, a genius plan in fact. And it was made more annoying by the fact that I could not for the life of me even begin to think of a way out. The dome broke down magic, and without oxygen, I was going to lose consciousness in a matter of minutes. I would have tested physical attacks against it, but the Killing Curse I'd sent earlier told me proximity to the dome increased the magic drain, and it didn't make sense to risk that for an unsure means of escape. Besides, physical exertion would have me using up my limited air even faster. 

So what could I do? Fuck all. There was not a single thing I could think of that would have any effect on my situation. Looking at it, it was a perfect trap. I already tried to Apparate twice and it had failed, Hogwarts' wards as airtight as they had always been. And then there was the fact that the portkey was inert. Touching the cup again did nothing. Instead of a two-way portkey like the one that had been used in the Goblet of Fire, it was clear that these agents of Voldemort were more confident than Pettigrew and Crouch. 

Why was I so sure they were Voldemort's men? Well, it was obvious. For one, who else would want me captured, but unharmed? It was clear that the Dark Lord intended to use me in his return somehow, and my only choice seemed to be to go along with it for the time being. Not like there was a choice one way or the other. There were two ways for me to fall unconscious here—magical exhaustion or suffocation. Magical exhaustion would have knock-on effects that would take days to recover from. Oxygen deprivation? Well, it was just a matter of getting some air back in me, wasn't it? And even if it wasn't, then I could carry my body with magic coursing through it. 

I wouldn't get the same effects from a fit body with no magic. The choice was simple then. So I began to do jumping jacks. As many of them as I could. Now, I could have just used a Somnum Charm to charm myself unconscious, but then there was no guarantee that they would deactivate the dome immediately. If they wanted me to keep breathing and not die in transit, which was definitely the case if they had gone through all this trouble, then they would deactivate the dome once I lost consciousness and that would save my magic from being sapped down to dangerous levels. At least that was the best I could come up with. 

And so I began. I began to jump up and down, executing a perfect jumping jack and making sure to do it with my mouth open and breathing heavily so I could run out of air as quickly as possible and so need to breath in more air to keep going. In short, the goal was to make my oxygen consumption as efficient as possible, while making the utilization as inefficient as possible. It took me a mere minute to begin to feel lightheaded. I knew this would be far from comfortable or painless, but it was better than the other opportunities by far. In less than another thirty seconds, I began to struggle to continue, and less than ten after that, I'd fallen to my knees involuntarily. My body was now struggling to take a breath, and before I knew it, darkness. 

XXX - SIRIUS BLACK 

He clicked his teeth with annoyance as he blocked two spells—one from each side. His spars with Harry had taken his skills to the point where even after 12 years in Azkaban, he was close to the level he had been in his youth. The only thing was that where he had grown used to fighting in a group of two—with his best friend, his partner in all things. "Bugger that, Sirius, get your head in the game! You can miss James later," he said to himself as he sent a Knee-Reversal Hex right in the way of his opponent's Vivisection Curse, forcing the both of them to ricochet wildly, uncontrollably, but not unpredictably. 

The Knee-Reversal Hex hit one of the ones that Flitwick was dueling with off to the side, and he nodded to the half-goblin's shouted thanks while the Vivisection Curse flew off into the distance. He cast a counter-curse that caused the Entrails-Expelling Curse the second one had been preparing to send his way to fizzle out at the end of his opponent's wand, not able to make any headway. He spun his wand counterclockwise and conjured a flock of birds that took a Killing Curse for him as he retaliated with a fire whip that dug into the first opponent's side. 

The second tried to take advantage of the fire whip and how the spell worked to catch Sirius by surprise with a bone breaker aimed at his neck. But he executed a perfect dodge, his head leaning out of the way right at the last second, and thus blocking the view of the spell until it was too late and the man that had been trying to sneak up on him from the other side ate the bone breaker to the face. The man's moans of pain died out as Sirius dispelled his fire whip with a flick of his wrist that he quickly transitioned into his next spell. 

"Schizo!" he barked, drawing on his rage, his hatred, and his desire to end the fight so he could focus on what mattered: looking for his godson. The spell from his Grandfather's personal library did as expected and tore through the man's Protego before cutting him in half. It left Sirius drained but had taken his list of opponents down from three to two, and of those two, one had taken a lancing blow from his fire whip while the other had taken a bone breaker to the face. 

He stormed them with a continuous barrage of hexes, jinxes, and schoolboy charms that he knew so well he could cast them in his sleep—for most of them, he actually had, more than a few times. The point of the barrage was to wear down the already injured fighters with the weight of the number of spells rather than the quality, and it worked like a clock. One fell to a Fever Hex, burning up before reacting too slowly as a result to deflect the Finger-Snapping Jinx that followed and forced him to drop his wand. From there, it was a classic Bowel-Loosening Hex that ended the fight, forcing the man to the floor as he emptied his bowels over and over again. 

The other acquitted himself only slightly better, managing to bear the Uncontrollable Sweat Hex for close to a minute, practically fighting blind as the sweat would have surely covered his vision, but eventually it was too much to handle and a simple mastubare harm was what did him in. Sirius just had to hope he went wherever James had because they would have a riot laughing at the sound the man made as he ejaculated in the middle of the duel. With both his opponents finished, he turned and began looking for someone who could give him answers. The first of which being, where the hell was his godson? 

A/N: And so we get the chappy. We see the end of the third task, and in true Hogwarts fashion, it's never a year-end unless something suitably dramatic happens. In this case, we get a borderline invasion of the school whose boundaries have proven extraordinarily porous over the session. Next four chapters up on patreon(https://www.patreon.com/c/Oghenevwogaga)( same username as here and link in bio), support me there and read them early.