Prologue - Farewell Earth
"Mr. Stark!" Screamed Subaru grasping for air in the middle of the battlefield. After all the events on Titan, after literally dying and coming back to life and getting smacked with the fact that he was deceased for five entire years by Dr. Strange, he was finally reunited with Tony only to see him struggling against another of Thanos' minions.
Quickly getting his wits about him, he shot his webs at the shoulders of the monster, making him trip right into Ant-man's path and getting stomped to death.
"Hey! Oh! Holy cow, you would not believe what's been going on! Do you remember when we were in space? And I got all dusty?"
Still trying to deny the reality of his death and the shame that filled him having had begged for his life to Tony just before being snapped out of existence, Subaru just blurted out his following lines. "Well I must have passed out because I woke up and you were gone but Dr. Strange was there, right? And he was like 'It's been five years, come on, they need us!' and then he started doing the yellow sparkly thingy that he does all the time and- What are you doing?"
Tony hugged Subaru.
This threw Subaru's mind for a loop for a second. Ever since his parents passed away when he was little during a trip to New York gone wrong, he felt he had lacked a proper father figure. Sure, after being adopted by Uncle Ben and Aunt May he came to love them just as much as he did his parents, and for a time Ben did feel like a father to him. Nevertheless, after losing him too in a robbery, the only one to recognize, respect and impart tough love like them was Tony Stark, his mentor. Having such a figure hug him just solidified Subaru's love for him as a father. And so, he hugged back. "Huh, this is nice."
They shared a brief moment of familiarity and hugged as though time had stopped. The battle still raged on however, so they would have to wait until later on to catch up and so, they went their separate ways once again in order to fight off the invaders. As the Mad Titan fought the Avengers, the struggle for the gauntlet grew fiercer, with the stones jumping from Hawkeye's hands onto Black Panther's and then onto Subaru. "Activate instant kill!" He yelled to his A.I., Karen, as the Outriders surround him. He desperately fought them back and, although confident at first on his relatively new suit, he eventually grew desperate the moment they began to overwhelm him. "Somebody help!"
"Hey Queens, heads up."
Holy crap! Did Captain America just threw Mjolnir? Thought Subaru. He thought it'd be so cool if he could lift a legendary weapon too. He flew across the battlefield once again, attaching himself to the hammer, then to Ms. Potts, or rather, Ms. Stark as the raining hellfire burnt his web away and then to a freaking Pegasus ridden by Valkyrie just to evade the fierce assault.
"Hey! Nice to meet youUUOOOH MY GOOOOooo-"
Although he put up a good effort, he ended up on the ground once again, needing the assistance of Captain Marvel and the others to protect the Gauntlet.
Things were looking up, all they needed was to get the stones onto the time machine Captain America talked over the intercom about and they would win, and with Captain Marvel going at full Speed towards the van and the rest of the Avengers slowing down Thanos the battle was pretty much set.
Or so he thought.
Thanos threw his sword at the machine making it explode and launching the gauntlet in his direction. Oh crap. He thought. Iron-Man rushed him, but he was easily knocked away, then Thor attempted to behead him, assisted by Captain America, but they too failed, being manhandled by the Mad Titan. Finally, Captain Marvel attempted to overpower him and for a moment it looked like she was successful, only for Thanos to detach the Power Stone from the Gauntlet and shoot her with an energy beam too powerful to even absorb, rendering her unconscious.
Oh crap, oh crap, oh crap! What do I do? What do I do? What do I do?! Subaru thought in a panic. It was just a repeat of their defeat, it all felt so pointless, what was the point of the whole struggle if they were going to lose anyway? What future did Strange even see if they were losin- Oh.
Subaru remembered. He remembered the words Strange gave him just before they left Titan.
"I can't tell you what is about to happen or how it's going to happen for if I do it will not happen, all I can say is that you must wait for my signal, so keep looking in my direction, okay?"
Subaru looked in Strange's direction, and he saw how he lifted his index finger up while restraining the water, rubble and enemy ships from flooding the battlefield, indicating that this was the moment. He could almost swear he saw his lips saying, "Forgive me."
Something in Subaru's mind clicked, The Avengers were on the ground, Thanos, was preparing himself to snap and the one nearest to the Mad Titan was himself. He realized that both the Gauntlet and his suit were Stark nanotechnology.
"Oh, I see now." He said to no one in particular, in an odd mix of both melancholy and acceptance. He realized what his purpose on this battle was and he prepared himself to meet his fate.
"Karen, there is no A.I. installed in the Gauntlet, right?
"…No, why?" Replied Karen, a tone of worry atypical to an artificial intelligence sprinkled in her response.
"The moment we touch it, I want you to transfer a command to any nano-bot still active in it to move the Infinity Stones from the Gauntlet onto the Iron Spider suit."
"?!" The A.I. responded with an alarming vibration, seemingly looking to express her worry. "Subaru, are you insane?! The sheer amount of cosmic energy and Gamma radiation running through the stones could kill you-"
"I know the risk Karen, but this is the only way, please…"
"…Understood."
"Thank you."
Thanos was ready to snap but just as he was about to do so, Subaru jumped onto his arm.
"Kid, what are you doing?" Tony managed to wake back up just in time to see Subaru latch onto the Mad Titan's hand.
"Insect!"
"Wrong, big guy!" As he said this, Thanos dealt a devastating blow to his liver, knocking him away a few meters back.
Thanos braced himself "I am…" He joined his middle finger and his thumb, basking in the imminent glory, "…Inevitable."
He snapped.
And nothing happened.
He stared at his arm in confusion, only to notice that the stones were not there. And then, the unthinkable happened.
Subaru got up from the floor, lifting his right hand in pain, seemingly struggling with even breathing as the Infinity Stones shone brightly onto the battlefield. Thanos was shocked, Tony and Steve were horrified, all the heroes and villains were astonished into silence and Strange… Strange looked remorseful as they all looked at Subaru as he uttered his retort to the Mad Titan:
"And I…"
He thought about his parents, he cursed the world for taking his parents away from him during the disaster that was Stark Expo and the attack from the Hammer drones, even if it lead to him meeting Iron-Man for the first time and being adopted by Ben and May Parker. What made him hate himself the most though, was the fact that he was the one that convinced them to go to that Expo in the first place, because of how huge of an Iron-Man fan he was.
"…Am…"
He thought about Uncle Ben and Aunt May. They took him in, they loved and raised him as though he was their own, and he repaid them by letting a robber kill Ben when he first got his powers. He would never live that down, always staying on his mind whenever he looked at his aunt, as a reminder of his failure. But what hurt him the most was that even though May knew, she still loved him regardless. It made him tear up even remembering it, just how good of a person she is for loving the fool that took her husband from her.
"Spider-Man."
Subaru snapped his fingers, and an ethereal light shone throughout the battlefield and the universe.
He opens his eyes, only to find himself in an infinite, golden colored expanse with the stones gone from his hand and the only thing ahead of him… the only people ahead of him his parents and Uncle Ben, smiling, waving.
"Mom… Dad? U-uu-uncle Ben?!" He responded in tears. He felt like running up to them, to hug them and cry his lungs away. But then, just as soon as they were there, they vanish, leaving in front of him two presences, standing right where they were. The first of the two entities was a silver haired… elf? And the second one clearly far more than that, yet he couldn't even begin to describe him… her? It? It was clearly… something above him, above anyone, standing just behind the elf with an ominous silence. And yet… he felt no hostility from it, just an immeasurable… care. From both the being and the elf. Although he also felt… grief coming from the elf girl. As he reached out to the girl, however, he woke back up into reality, just in time to witness the end of the battle.
A leviathan was about to devour Rocket only to vanish into thin air. Outriders fighting Wakandans, Asgardians and all the warriors and heroes on the battlefield turned to dust one by one. Thanos' ship and his numerous vehicles and soldiers became dust in the wind, followed by his abominable Black Order, with Ebony Maw reaching a hand towards his master only to disappear into the oblivion. The Avengers admired the result with conflicted faces, watching as their enemies panicked before ceasing to exist, until finally only the Mad Titan remained. Thanos looked around himself, his expression one of surprise, then melancholy and then reluctance. He sat on the rubble created by his raining fire, contemplating his life up until that point one last time, before vanishing with an unfinished sigh.
Thanos was dead, the threat is over, they have won.
It's a joyous occasion, the universe is saved, the boy did it, except… said boy was struggling for his life at the moment.
"GHK!" Subaru managed to gasp as he unceremoniously let the stones hit the floor, detaching them from his right hand's fried armor piece. Even after he did this however, the residual cosmic energy, magic and beyond that coursed through him threatened to leak out and explode, his body barely containing it.
"Kid, kid, stay with me okay?!" Tony panicked. He knew it was futile, his brilliant mind screamed at him so yet his heart refused to listen. "You are going to be fine, you are going to be-"
"Boss, the energy coursing through him is similar to the Asgardian Bifrost bridge, its leaking and surrounding him, I'm afraid there is little we can do to-"
"Shut up Friday, Shut up! He can't die. He just can't! What would be the meaning… what do I tell his aun-"
"We won Mr. Stark! We won!"
Tony looked at Subaru, befuddled. "…Why are you smiling?"
Subaru was smiling at Tony, even though he was in clear pain, tearing up even, he smiled and reassured him. He had made peace with his decision, and he didn't regret it, because it would mean that his hero, the man that inspired him, that saved his life, that gave meaning to him, would get to go back to his family, to his wife and to his daughter. Subaru understood, that on those five years he was gone, Tony had made a family for himself, that he wasn't alone anymore, that there would be people for him to protect, to mentor and nurture even if he wasn't around.
He thought about Aunt May, he felt bad about her, he was leaving just as he came back, but he figured, with the looks Happy would give her from time to time and how she responded, she'd be fine too. She would not be alone.
He thought about Ned. Did they complete that Death Star? Oh yeah, they did. But they didn't get to see the MoMa. But that's okay, he would always be his guy in the chair.
He thought about everyone really… MJ, Liz, her dad and even Flash. And… he was glad. They would be okay. They would be safe. Alive and together with their families once again.
"The energy is reaching its peak, we can't do anything…"
"Subaru…"
"It's okay Mr. Stark." Subaru leaked a tear. "We won." And his smile, although trembling, remained.
And suddenly, his body was completely enveloped in the Bifrost-like rainbow. As though he was never there in the first place he vanished into light particles, not even leaving a trace behind.
"SUBARU!" Tony yelled as he teared and cried his eyes out. Pepper too teared and hugged him as Tony fell to his knees. One by one, the Avengers and the warriors kneeled towards the direction their youngest member had vanished from. All looked remorseful, someone so young should not have carried their burden, and yet, all they could was lament. As Earth has just lost its youngest and most noble hero.
…
Meanwhile in another world, in another planet…
"Mmmm… Delightful, it seems the day has finally co~me." a strange noble man with a clown's visage utters as he sips on his late morning tea while overlooking his domain.
It seems as though Spider-Man, Natsuki Subaru's adventures, had yet to end. Perhaps, they are only just beginning.
AUTHOR'S NOTES
So, this is my first fanfic. I'm just basically toying with the idea of introducing the Marvel Multiverse to the Re:zero cast and thinking the ensuing madness would be funny, to say the least. And I thought that the best way to do so would be with Subaru being an Avenger, MCU spidey. He will still have Return By Death but because I want him to show off that Stark Tech and intellect of his, he won't be using or needing it right away. If anything, it'll come into play way later, once I'm done with the first few arcs, when I introduce the straight up cosmic or technologically advanced stuff. So, for the beginning I'll just focus on the clash of cultures and behaviors. I welcome any ideas and corrections (english is not my first language), though do expect me to pull from the comics and cartoons if I think it's entertaining enough.