I own nothing relating to any series, including Harry Potter and Marvel.

Inspired by On A Pale Horse by Hyliian.

Rider in the Night

Chapter 1

'I wonder how long it's been,' Harry thought to himself, 'since I ascended.' It wasn't something he thought about often. And not just because he was often using beyond lethal amounts of peyote and tripping so hard that he would more than likely end up on Jupiter… again.

All it had taken was one Death Eater with a grudge and woeful ignorance - which, considering how isolated magical society had been, that was quite easy to find - of the damage he would cause upon unleashing nuclear hell on the world. One missile launch prompted a dozen others and it avalanched from there until Earth was a nuclear wasteland.

There were maybe six million people left on the planet and it dropped quickly due to radiation poisoning, lack of sustainable food and so on.

He survived because of what he was. The whole 'Master of Death' thing was a misnomer, sort of. While not wrong, per say, he basically just became master of an automatic process. He didn't have to do anything and things still lived and died as per the natural order.

It was, perhaps, more accurate to call him 'Death' rather than 'Master of', with the amount of control he had over the system. He didn't like to, considering that death was often a means to end suffering and delaying that was considerably worse than not, his own life not included.

Despite the phenomenal cosmic power he ended up having, it had still taken him a few thousand years to reverse what had been done and stop the Death Eater before he caused a nuclear apocalypse. However, stopping the fact he had survived a nuclear bomb did nothing to change him back. He was still Death and it was clear that he would always be Death.

Not far from him, at this very moment rather than in his memories, slept a wonderful Native American woman, who had been teaching him their native magic in the decades before they were wiped out by the invading Colonist. Time travel was a handy trick and he had been using it for… an ungodly amount of time to learn about magic in both the future and the past.

In return for her help, he had shared a few forms of healing magic and hygiene spells. One thing led to another and, well, her clothes were somewhere nearby and he would be sure to make sure she had them as soon as she wanted them, and as soon as he sobered up. Peyote was… fun.

And then he felt it. It was like a tugging, faint though it was, like someone had tied a thread around one of his ribs and was pulling on it. He felt an initial flash of irritation - Who goes and ties things around people's ribs? Honestly! - before he realized that this was different. He was being summoned!

He sobered himself immediately, his eyes became unfocused as he traced the magic to its source, a bit of shock crossing his face after the briefest of moments.

The tether of magic that had attached itself to him stretched considerably far. Impossibly far. Outside the edge of the universe and into the void. Or, perhaps, the void between realities? If there was something out there that meant there was another reality, right?

He brought up the memories of the deceased, sifting through it for something that matched or was similar to what he was going through. The knowledge he brought up said it was possible, but traveling to one would take enough energy to extinguish a variable hypergiant with a radius around seventeen hundred times larger than the radius of the sun and leave nothing behind.

But then, magic rarely followed normal rules. In fact, he could count on his fingers the number of rules it followed and have fingers left over. Basically, magic did what it wanted, so long as a person could provide power, and magic only followed the rules people put on it.

He idly plucked the cord wrapped around his rib as he considered his options. Unknown persons looking to summon him to another dimension. They weren't looking for him specifically - the Harry Potter him, not Death, though he doubted they were looking for Death either - and the magic was unable to tell him since it only sought to do what it was made to do and had no way of transmitting information. So he'd be going in a potentially hostile environment and he was unaware of whether or not his powers would be stripped from him.

Not likely, as reversing time and killing himself as a newborn hadn't done jack besides monumentally fuck up the timeline, leaving him utterly unaffected. And, if they were hostile, they'd have to deal with a pissed off embodiment of Death, which would end poorly for them

He set up a tether that would, regardless of any possibility, allow him to pull himself to this exact place and time. Plus having a way back in general was smart, just in case he couldn't otherwise.

To make it a bit easier on the magic summoning him, he Stepped to the edge of reality and allowed himself to be pulled out, his heart beating a lightyear a minute as he wandered into the unknown.

~Z~

'Don't Call Me' Nymphadora Tonks did not like the plan Dumbledore decided on.

She had joined the Order of the Phoenix on the recommendation of her partner slash superior, Kingsley Shacklebolt. She hadn't entirely believed that You-Know-Who had returned to life, but it was clear his Death Eaters were becoming more active. Since the Ministry was sitting around, twiddling their thumbs, she joined a group that originally seemed like they were going to stop the Death Eaters.

But the only thing they had done in over a year was guard the Prophecy Room in the Department of Mysteries - poorly guard, she might add - and keep Neville Longbottom, quote unquote, protected during the summer after the supposed resurrection of You-Know-Who.

Unfortunately, his relatives were about as emotionally supportive as a rock, if not worse. They weren't physically abusive, thankfully, but that was a small comfort considering everything that had happened in his life.

Dumbledore also wanted her to relay any information Kingsley couldn't get, ignoring how illegal it was for her to do so. While she couldn't speak for Kingsley, she refused to do so. She might've joined a vigilante group, but she wasn't going to perform illegal actions when all she wanted to do was stop the Death Eaters from starting the war back up.

Then Neville broke into the Ministry of Magic in an attempt to rescue his father from You-Know-Who's grasp. It had been a trap, but Neville hadn't cared, wanting to save the only parents he had left, even if Frank had a psychotic break back when Neville had been one. It ended up with Frank being killed by Bellatrix Lestrange, Neville being seriously injured and with Hermione almost dying.

And then Dumbledore had the gall to say that they - he was speaking to the Order but she could tell he was talking about Neville - 'weren't cutting it' and that they should summon a 'hero' (the actual term used was 'Vanquisher of Voldemort') from another dimension and then somehow convince this unfortunate person into helping them with their own Dark Lord problem.

Tonks didn't know where Dumbledore got this ritual from, but she had a feeling it wouldn't end up anything close to how he wanted.

She rather doubted that any 'vanquisher' they summoned would be in any sort of mind to actually help them. If someone pulled her from her dimension by dubiously legal means and expected him to fight their war for them, she'd probably laugh in their faces, tell them to go to hell, and to do creative things to themselves with a nearby chair leg while they were at it. There were just so many things that could go wrong with this ritual, and Tonks was slightly horrified with herself that she let Dumbledore talk her into actually being present for this abomination, even if she managed to wiggle out of actively participating.

The magic had gotten progressively thicker until it was a little hard to breathe, until it leveled out at the point where Dumbledore had told them that the ritual was making contact with the 'hero' on the other side. This was necessary because, apparently, the magic was supposed to implant a compulsion in the recipient to follow the pull back to this dimension - which was illegal, but she had been outvoted on the matter and would be punished severely by both parties if she told the Ministry - and encourage them to come along without fighting the ritual, which could damage all parties involved.

What was not supposed to happen was the magic pull being pulled back. The whole room seemed to jerk in place, as if some sort of god had just grabbed ahold of reality and yanked on it. Everyone began talking over each other in shock and surprise, wondering what had just happened and if the ritual was working right, as the uneasy feeling in Tonks grew.

Almost without thought, her pink eyes met black as the only other protesting party met her gaze from across the room. Incredulously, Tonks realized that only she and Snape seemed to have realized that the ritual worked just fine. It was just… whatever they'd hooked on the end of their line was far, far bigger than they were.

"Guys…?" Neville, who was barely able to stand and was getting some support from both her and Hermione, said, going largely unheard in the chaos, but pressing on regardless. "This is a really bad idea."

He was, of course, ignored.

Dumbledore twinkled reassuringly at them all, raising his hands benevolently as a gesture for calm. "Please, settle down everyone. The ritual is working correctly; we simply miscalculated how much power it must take to cross dimensions in such a fashion." And as if to prove this statement, the magic in the air doubled itself as Dumbledore obviously pushed himself even further, which slightly impressed Tonks, but she was far too horrified to honestly care about how much magic the old man was throwing around.

Just as she thought the magic in the air would drown them all, it all seemed to be sucked to the middle of the room just as the air ripped itself in half. A huge, jagged crack had just appeared in midair, showing nothing but empty, formless black on the other side. Her unease tripled itself.

A strong looking hand gently curled around one edge of the tear in reality, a large silver ring set with a black stone adorning one finger as a bare leg stepped out of the rip and onto the wooden floor, which blackened and began to rot immediately. A man, one who Tonks might've thrown herself at had it not been for his terrifying aura, emerged from the crack as if this sort of thing happened every day, draped in nothing more than his birthday suit, and the tear sealed itself up behind him as if it had never been.

"Albus Dumbledore…" the man hissed, a rattling sound that bypassed their ears, speaking directly to their very souls. Tonks inhaled deep, desperate for air, and wondered just what sort of monster Dumbledore had called here. The pure hatred in his eyes would've been visible for miles, "You… summoned me?" Had she not gone to the bathroom before the ritual started, Tonks would've wet herself in fear.

~Z~

The trip through the void had been fun. It reminded him a bit of flying on his broom during his years at Hogwarts, except he was flying between stars so tightly compacted that it was a surprise they didn't merge into one.

That was about as well as he could explain traveling in the multiverse. On the bright side, now that he had been pulled out into it, he could access it at will. And he could feel… things in between that would've shattered his psyche had he still been human but were absolutely terrified of him. It boosted his ego a bit but left him curious about what the things were.

Of course, he had to flex his powers a little in order to properly scare some of the more powerful creatures out there, but being the embodiment of death had its benefits and even those things ran off in fear.

He stopped a hair short from the edge of the reality he was summoned to, resisting the tugging just to make sure he was orientated the right way. He might've been all powerful, but that didn't mean magical travel liked him any more than it did before his transformation.

Checking to make sure he had everything - head, shoulders, knees, man-bits, toes, everything important - he couldn't shake the feeling he forgot something. Shrugging to himself, which was a bit odd to do in the space between realities, he reached forward into the crack in reality, fingers pressing against air solidified with magic just to make sure he had a handhold, before he pulled himself through.

He was stunned to see his old allies and classmates but, considering he had just connected to an infinite multiverse, it was far from impossible.

He could also tell, from the moment he emerged into this reality, that there had been a Death already present. Not only that, she had immediately pledged loyalty to him before dumping her duty onto him. He could already feel the departing souls passing through him in a river parallel to the ones he could still feel from his original world.

Still, despite the fact she was clearly lazy, it would be nice to have another supposed immortal to talk to. And he couldn't fault her. Thirteen billion years without someone like you was a horrifying thought. He had been without someone like him for a few hundred thousand and he was starting to grow detached.

And then he spotted Dumbledore.

He knew that this Dumbledore was different than his own, but emotions didn't care about that.

A hundred attempts. He had given his version of Dumbledore a hundred attempts at redeeming himself for purposefully making his life a living hell, and every change just made a worse Dumbledore.

Making it so his sister wasn't assaulted led him to joining Grindelwald on his conquest and the Axis won their World War. Preventing Ariana from dying led him to killing and replacing Grindelwald, with the Allies continuing their sweep of the world until nothing happened without their say so. So many changes and most of them led to Dumbledore becoming a Dark Lord, or some kind of master manipulator, where he controlled the British Wizarding World from the shadows.

While he stopped himself from outright killing the old wizard, Harry glared at him with nothing but loathing. "Albus Dumbledore," he hissed out, the man going ramrod straight like he was an army grunt and Harry was his commanding sergeant. "You… summoned me?"

When Dumbledore didn't respond, he glanced around the room again. He recognized every face in the room, and he even recognized the room, but there was someone there that shouldn't have been. His eyes settled on Neville Longbottom, taking a brief flick upwards to look at the dark, angry scar on his forehead.

And then Harry blinked. "Ah, shit. I'm naked, aren't I?" He looked down at himself and, sure enough, he wasn't wearing anything. He reached down, smoothing the shirt that hadn't been there an instant prior. In fact, he was now fully clothed, though he looked like someone comfortable in his own house rather than someone who had just been summoned.

He had chosen simple clothing, a plain white shirt, black tracksuit pants with a white stripe down the side and black and white sandals. He might not have been the most fashionable around, he hadn't reached that phase of his life yet, but even he didn't make the mistake of putting socks on with his sandals.

And then he heard a girlish giggle, finally breaking the silence of the room. His eyes flicked over to Nymphadora Tonks, who would probably hit him if he said her first name if she were anything like his. Her giggles quickly turned into a laugh, which then saw her snorting as tears streamed down her face.

He raised a brow at her. She was relieved and he could not tell why. Of course, her laughter of relief was monumentally better than the other relief half the people in the room had.

"I'm- I'm sorry," the emerald-haired girl stuttered out slightly. "You just scared half of us to near-death, including Albus Bloody Dumbledore, and the other half soiled themselves, and you did it naked." She then snorted again, "And then- and then you just have clothes on, like they were there to begin with!" She burst out into a fit of giggles again, despite the otherwise silence of the room.

Harry smirked. He had to admit, the situation was funny. It was funnier when he thought about the fact he scared off creatures that would make Lovecraftian Horrors shudder in fear whilst being buck naked.

Deciding to humor himself, he started to turn around the room, pausing to look at people and saying their name. "Nymphadora Vulpecula Tonks, Neville Franklin Longbottom, Hermione Jean Granger, Albus Percival Dumbledore -" The old man shot him a nasty glare but Harry ignored him, "Alastor Bartholomew Moody, Sirius Orion Black, Remus John Lupin, Dedalus Icarus Diggle, Severus Tobias Snape, Mundungus Rupert Fletcher, Emmeline Antoinette Vance, Hestia Diane Jones, Minerva Isabelle McGonagall, Kingsley Tiberius Shacklebolt, Arthur Septimus Weasley, William Arthur Weasley, Molly Melody Weasley."

Harry hummed, "I suppose Podmore's in the hospital still and Hagrid's too big to get in here. But you've got most of the party. I take it the other kids are upstairs?"

"I suppose you know us from your reality," Dumbledore said, puffing his chest out, as if he weren't just terrified. "You were a member of my Order?"

Harry didn't miss Dumbledore's claim of ownership over the group, even one not his own, but he ignored it for the moment. "No. But I was the reason you reformed the group," he said, intentionally misleading so Dumbledore would get the wrong idea. Messing with the old man was always fun.

He wasn't disappointed when Dumbledore paled. "Yes, well," The old man hesitated. "You are no doubt curious as to why I summoned you."

Harry didn't miss the implication that Dumbledore did it alone, despite the clear signs of magical exhaustion around the room. He hummed, "I suppose so." Harry then grinned maliciously, "So tell me Albus, why have you summoned me?"

"I wish to negotiate a contract," Dumbledore clearly stated. He pulled a parchment off the table next to him, taking a brief glance over it before he extended it over. "It should be signed swiftly, there is much to do and little time to do it in."

Harry kept smiling, taking the contract and sitting down, complete with a comfortable chair, grand wooden desk and full lawyer assemble, including suit and reading glasses. As he read the contract, which was clearly unconscionable, he conjured a black parchment and wrote with silver ink that etched itself into the dark hide.

"What is it you are doing?" Dumbledore asked, sounding remotely confused, which meant he was completely baffled.

"Writing," Harry replied. "You wish to make a deal with your terms, I counter with my own. That's negotiation."

"There is nothing wrong with my contract," Dumbledore said, sounding offended.

The entire room was still silent, the only ones to have talked being Dumbledore, Harry and Tonks. Though the others started to move, mostly grabbing wands and vanishing messes made, they were still silent. Harry would've found it annoying if he wasn't currently amused.

"I never said it was," Harry replied. "If that's your first train of thought after I mention writing my own, perhaps I should share the details of the contract with the others…"

"I had only meant that there is no need to negotiate, the details of the contract are perfectly fair," Dumbledore retaliated.

"Section Seven," Harry started, "subsection one-..."

"If you think it is necessary," Dumbledore interrupted him, "then go right ahead."

Harry rolled his eyes. Ignoring Dumbledore's gracious acquiescence, he set down the contract from Dumbledore and raised his hand, snapping his fingers. "Attention, attention," he said like he was speaking to school children. Which he basically was, considering he was significantly older than all of them, even if their ages were combined and multiplied by one hundred. "We have now reached the boring part of this. Anyone who doesn't want to remain here may leave. In fact, I insist on it."

He didn't look up from his writing, but he knew a few people looked to Dumbledore for permission. "You may all leave, if you so desire," Dumbledore said, which began the sounds of people shuffling out of the room.

"Wait," Harry said, stopping them all. "Neville, you stay. I have a feeling you will be involved in the contract, whether I like it or not."

Neville nodded and Hermione guided him over to a plush looking chair. "I'll be back in a moment," Hermione whispered and Neville nodded again.

As Harry finished the contract and slid it across the desk to Dumbledore, he looked over at the green-haired metamorphmagus that had, after making sure Neville was alright, walked over and watched him. "How can I help you, Tonks?" Harry asked, a gentle smile on his face.

She slapped him upside his head. Twice. "You said my full name," she said, with a little heat. "If you know me well enough to know my name, you know not to use it." She paused a second before talking again, "You were able to conjure a bunch of things as if they were already there, couldn't you have just conjured up a completed contract.

Harry chuckled, fingers combing through his untamable hair. Even he couldn't fix that, for whatever reason. "Fair enough, I suppose," he said, shrugging off her hitting him. It might've upset him long ago, but it didn't anymore. "I could have, yes, but where's the fun in that?"

What he didn't say was that Dumbledore's contract was incredibly unfair and one-sided, something he reflected when he wrote his own version. "What is this?" Dumbledore asked, and Harry could see the pulsing veins of barely controlled anger from the old wizard. Well, young by Harry's standards, but he didn't count.

"A contract equal to the one you have given me," Harry stated. "But one that benefits me rather than you." He knew that Dumbledore couldn't cause an outburst with Neville around, as he was the Boy Who Lived and Dumbledore's tool, and he was already on shaky grounds with Tonks, given the compulsions laced into both the spell to summon him and the contract he had been handed.

"Perhaps something… a little more simple then?" Dumbledore asked. "Since I doubt either of us are willing to let the other guide them, as the contracts stated-"

Harry snorted. Guide was putting it lightly. It wasn't a slave contract, but closer to indentured servitude. It was as close to slavery as was allowed in the magical world, outside of House Elves. "Simple, huh?" Harry asked after a moment. "How about this? You tell me what you summoned me here for, with no pleasantries. Tell me your plan like a Gryffindor, not a Slytherin."

Dumbledore raised a brow. No doubt he was debating on whether he should or not. Eventually, he nodded and pulled out his wand, conjuring a plush chair. After getting himself comfortable, during which Harry didn't move, he looked over to Tonks, "I would appreciate a moment alone with our new friend, my dear. Why don't you take Neville and allow us a moment."

"Neville stays," Harry stated. "This talk will involve Voldemort and there's no one else here that's had their life affected more than him." Not entirely true, but it was for someone originating in this reality, which Harry was assuredly not.

Dumbledore gave a brief sigh, "Very well. A moment, my dear?"

Tonks pursed her lips, looking unhappy but being forced to go along with it. Though it didn't seem that Dumbledore had noticed her taking his version of the contract, and Harry wasn't going to say anything about it.

Once she had left the room, Dumbledore turned to Harry, giving just a brief glance to Neville, "What do you know of the Dark Lord Voldemort?"

"Egomaniacal, power hungry, death fearing narcissist who used the pureblood ideology to indirectly gain political power and cause a lot of fear, despite being born to a borderline squib and a muggle," Harry replied. "Real name Thomas Marvolo Riddle, though he went by Tom during his Hogwarts years, created seven horcruxes, each of which, except the last one, were based around what he considered one of the moments that shaped him. His first murder, his first betrayal, etcetera."

"You mean seven pieces of soul?" Dumbledore asked.

"No. Well, sort of." Harry scratched his head, "He separated seven pieces of his soul from himself, the last one unintentionally, but they all act like anchors, keeping him from passing on."

"You know what they are?" Dumbledore asked. "You know where they are?"

"Yes and yes," Harry said. "I can go get rid of them now, if that's the deal you want to make. Making Tom mortal would be indescribably easy, and I wouldn't mind doing it again."

Dumbledore hesitated. It was clear he wanted to accept but wasn't sure if he should. After a moment, he spoke again, "There is a prophecy. I only wish for Voldemort to be without his power base. His followers… you may do with them as you see fit."

"Prophecy means very little in the face of overwhelming power." Harry stated simply. "But to each their own. Unless specifically asked otherwise, I will not harm the homunculus that goes by the name of Voldemort. As they are not a part of his physical being, his external pieces of soul do not count.

"Now let's talk about my compensation," Harry smiled. It was far from friendly.

"We have gold and jewels-" Dumbledore started before Harry interrupted.

"Worldly trinkets, nothing more," Harry stated. "I don't care for it, never have. No, I'd like knowledge. Your knowledge of magic and magic theory, especially the ritual you used to summon me in the first place."

Dumbledore was silent for a moment, mulling it over. "If you also agree not to harm my people, I believe we have an agreement."

"My word is law," Harry said as he extended a hand to Dumbledore.

Thinking he was getting a fair deal, Dumbledore took his hand and shook it.

"The deal is made," Harry stated. "It might be my actions that cause their deaths, but it is your hands that will be covered in their blood."

He stood from the chair, the furniture he conjured disappearing as soon as he stopped touching them. He turned and walked towards Neville. "That's one," he said, reaching forward and physically removing the scar from Neville's forehead, never touching the nervous boy.

Harry cackled, a deep, chilling sound that filled mortals with dread. With nary a moment of pause, he crushed the dark soul fragment, erasing it entirely. Of course, given he was rather benevolent, he also restored Neville's body and soul, patching him back together. So long as he wasn't hit with another killing curse for a couple years, he would be fine.

"What- what are you?" Dumbledore asked.

"Screw that!" Neville shouted, breaking his silence. "What did you do to me? What was that?"

"I removed a piece of foreign soul attached to you through your scar, one belonging to the homunculus known as Voldemort." Harry hummed, "As for what I am? I am the Embodiment of Entropy and Negentropy. I am he who shall stand at the end of all things. When the last living thing dies, I'll put the chairs on the table, turn out the lights and lock the universe behind me when I leave."

As Harry talked, he grew progressively taller and less human in appearance, eventually becoming little more than a black-cloaked skeleton, taller than Hagrid and carrying a scythe larger than he was. It was mostly for show, but he wanted Dumbledore to know that, regardless of what he thought, he was not in charge. "I, little mortals," Harry said in a cold, grating voice that was felt with their souls more than it was heard, "am Death."

Author Notes

The idea behind this was Harry became the equivalent of Death of the Endless (from DC Comics), with the power to back up his newfound position. As such, this is a Harry that is so Overpowered that he goes beyond the realm of being overpowered and into the realm of the absurd. However, I tried to keep his humanity, rather than have him act as one would expect the cosmic embodiment of death would be.

While this is a Marvel Crossover, I am aware I didn't add much of anything to this chapter. Rest assured, I will start adding some in come next chapter (whenever that happens).

Entropy: Lack of order or predictability. A gradual decline into disorder.

Negentropy: Negative entropy. Order and predictability. A gradual increase of order.