Disclaimer the following is a non-profit fan based AU crossover, Steven Universe is owned by Cartoon Network and Rebecca sugar, iron man and Captain America are all owned by Stan Lee (R.I.P), Disney, marvel comics please support the official release

before we begin, I just want to say that this crossover Steven Universe fanfiction was inspired by Samuel152's batman/Steven Universe crossover, please be sure to follow him and check out his stories and support his work

this crossover will follow the Steven universe story but with help from Iron Man and Captain America, as they fight alongside the crystal gems, fighting the corrupted gems, and eventually, homeworld itself, with some AU changes

this is also my first Steven Universe fanfiction by the way, mixing it with two of marvel's heroes too, I was a bit nervous at first, but eventually, I got inspired to start writing this story, any constructive criticism is welcome here, but please no swearing

here are the changes in this AU crossover, and where everyone is right now

Steven Universe

Steven is 14 

Steven and connie have met after bubble buddies

Steven has passed the crystal gems' test

pearl and amethyst have learned to fuse

Steven Universe (AU changes)

Steven and connie are just friends (i'm not good with romance, sorry)  

the diamonds use shapeshifting more often to change size

greg is more responsible and teaches Steven homeschool alongside pearl

Steven has a medical profile and has been at the hospital before

each of the diamonds have their own weapons

the diamonds powers work on humans (except destabilization from yellow diamond)

the maheswarans are more supportive of connie from the start, and are much less strict and made sure connie was a circle of friends

iron man (comics)

Tony stark is CEO of stark international2 years after extremis has been purged from tony's bodyafter axel reverse personality crisis

Iron Man (AU changes)

Tony is still using the model prime armor
The model prime has bleeding edge armor elements mixed into it, (excluding being stored inside tony's body and the R.T node chest implant)
Tony has his heart shrapnel removed
The model prime armor backstory is changed
The model prime armor has more modes/forms
Civil war I and II never happened
The superhuman registration act never came to pass
The AI is J.A.R.V.I.S. (F.R.I.D.A.Y's cool, but I honestly prefer J.A.R.V.I.S)
Tony still has a secret identity
Tony has contacts with S.H.I.E.L.D.
Tony never drank (i don't write alcoholism)
War Machine is still active and alive

Tony has better social skills

Captain America (comics)

5 years since Captain America was thawed from ice after World War II

Captain America had been welcomed into the avengers

S.H.I.E.L.D. had accepted Captain America into their ranks

Captain America (AU changes)

Captain america is working part time with S.H.I.E.L.D.
Steve rogers is close friends with tony stark
He has a motor cycle
S.H.I.E.L.D. keeps Steve rogers' identity from becoming public knowledge
Maria Hill is not part of S.H.I.E.L.D

and now, let us begin our story

on the oceanside town called beach city, there lived a young boy and his three guardians, they were known as the crystal gems, they had been living on earth for thousands of years after a rebellion against their homeworld afterward they had been going on missions to poof and bubble every corrupted gem the crystal gems could find, which came as a result of the aftermath of the rebellion, while also looking after the young boy, named steven universe who possess abilities inherited by his mother and the former leader of the crystal gems, rose quartz

during the times the crystal gems had gone out for missions, steven would spend his time watching his tv, playing video games, and would occasionally read comic books, but while watching the news one day and the comics, there's one thing that stood out to the young boy and had him starstruck from stories about two superheroes from the news

Iron Man and Captain America

Granted, there was a whole community of heroes out there, outside of beach city, but those two stood out to steven. He would ask his father about recording any news sections about either iron man, captain America, or both.

Most of the time, steven had wished he would be like them, out there with the crystal gems when they are out on missions looking for corrupted gems. Iron man looked like the pinnacle of technological achievement. Captain America, on the other hand, was something else,

iron man interested steven greatly, his armor especially, and the technology used in the armor wasn't like anything steven has seen before in beach city, earth-wise anyway, whoever built iron man's armor and his technology must be very rich

what stood out to steven from captain America was his many feats, including his fighting spirit, his unwillingness to give up no matter what the odds were, and he and steven share a thing in common, they both have shields they can throw like a boomerang,

and they both seemed so natural. Steven had his shy friend Connie marashawan come over one time to watch one such news section. She, too, was amazed, and they both wondered, what would it be like if either of those two heroes were in beach city, fighting alongside the crystal gems...

one day, after coming home from a monthly hospital checkup, steven's father Greg was walking him home to the crystal temple, the home of the crystal gems

"It sure feels good to be home, dad!" smiled steven, going through the door to the beach house,

"It sure does schtu-ball," said Greg, following his son inside

"Hello, steven," greeted a soft British voice belonging to a tall Indian red-skinned woman with a cube-shaped afro, a black and crimson bodysuit, and wore triangular futuristic visors covering her eyes, named garnet.

"hi, garnet!" smiled steven "where's pearl and amethyst?"

"they're out on a mission right now," said garnet, moving aside as steven and Greg stepped inside "how was the hospital?"

"The doctor said steven's doing okay," said Greg, explaining today's checkup "no sign of sickness. He'll be alright."

"that's good," nodded garnet,

"the doctor seemed nice," said Steven and then walked up the stairs to his small room above the couch. "I wonder what's on today."

"well, there's only one way to find out stchtu-ball," smiled Greg, already imagining his son's enthusiasm

"you're right, dad!" cheered steven, grabbing the remote and turning on the latest news report outside of beach city, and a man's voice spoke.

"in the news today, iron man has once again foiled a heist and stopped an armored truck from getting away with a lot of money and stark technology. Tony Stark, CEO of Stark industries, is glad to have the stolen technology in one piece thanks to his bodyguard, iron man, Ronnie?"

steven felt literal stars in his eyes as he watched iron man stop the armored truck with his bare metal hands and made short work of the robbers from the news clip despite the stolen stark technology, then the other news rolled up as a woman's voice then took over

"thank you, max. In other news, S.H.I.E.L.D agents were on the scene as Captain America helped lead the charge against HYDRA soldiers at a warehouse later today, who were preparing to smuggle weapons to a crime syndicate, the squad's leader, crossbones fought Captain America, where the star-spangled hero emerged the victor and had the mercenary taken into S.H.I.E.L.D custody."

Steven felt awestruck as he saw captain America lead the shield agents to battle as a hope bringer and an inspiration to push back the HYDRA agents. Captain America pushed back the bullets and lasers with his red, white, and blue shield and took on crossbones with his bare hands while also using his shield like a boomerang, knocking the HYDRA troops overhead. Even when crossbones seemed to be gaining the upper hand, the super-soldier refused to give up and eventually defeated crossbones with strategy, hauling him away to a S.H.I.E.L.D van to the Raft prison facility.

"they're so awesome!" awed steven "sometimes I wish they could be here alongside us..."

"He really loves it when those two come on TV," chuckled Greg, awing his son's enthusiasm.

Suddenly, a blue streak of light shot out from a crystalline pad in the inner part of the living room. Steven and Greg turned their attention to the warp pad. The brightly colored beam then dissipated to reveal a tall, slender, thin-built woman with ivory skin, an aqua blue tunic, and light cyan eyes, with a pearl gem on her forehead and a short bright lilac-colored skin girl with a mauve oversized, off shoulder tank top, with an amethyst gem on her chest emerged from the warp pad.

"yo, ste-man!" called the purple gem.

"Hi, amethyst! Hi, pearl!" said steven

"hi steven!" chimed pearl as she stepped off the warp pad, "how have you been?"

"oh, I've been doing okay, I just got back from the doctor's today!" said steven

"don't worry, he'll be fine," answered garnet

"well, that's good to hear!" said amethyst as she went to join steven upstairs "so what are ya watchin'?"

"We were watching another news report on Iron Man and Captain America!" said steven

"iron man?" asked amethyst, raising an eyebrow, "Captain America? who are they?"

"they're superheroes like you guys in a way!" said steven, expressing his basic thoughts of the two heroes "they protect the earth from bad guys!"

"whoa, really?" awed amethyst "fighting to protect earth like us?"

"Yeah!" cheered steven. As he gushed, garnet felt like she had foreseen a vision of the two heroes.

"um, steven," said Pearl, "this iron man and Captain America are not real..."

"w-what?" gasped steven, feeling a little crushed "but why!?"

"because television is fictional, steven," said pearl, "everything on tv is not real. It's just for entertainment."

"but pearl, they are real," countered Greg "there are stories and tales about those two from around the world, heck there's a whole community of heroes too!"

"humans fighting for the earth?" said pearl. "this seems relatively superficial..."

"but pearl! It's true!" said steven "there's real heroes out there like Iron Man and Captain America. they're like us."

"But how are we like those two if they are real?" asked amethyst. "I'm having a hard time believin' this!"

"believe me, amethyst, please!" pleaded steven "iron man and Captain America protect the earth as we do in their own way!"

"steven, it sounds like this iron man and this Captain America seem similar to us.", but trust me, they're not real. If anything, they're probably only doing this for attention, and everything is for entertainment on TV."

"but pearl..." said steven, looking a little sad

"steven," spoke garnet before pearl could retort again, "may we speak in private outside?"

"huh?" said steven, turning his attention to garnet "um, sure garnet, I'll be right out."

"I'll come too, steven," said Greg, following his son outside

garnet then opened the door, leading steven and Greg outside of the house and onto the beautiful beach where the ocean waves washed over the sand

"what did you want to talk about in private garnet?" said steven

"two things," said garnet, placing her hands on steven's shoulders. The young boy felt the two gems on his shoulders, "first, can you explain iron man as best as you and Greg can?"

"do you believe me, garnet?" said steven, hopeful

"yes, but please explain him to me," nodded garnet in a stotic yet soft tone.

"we'll do our best garnet," said Greg, joining in on the conversation

"Okay..." breathed steven and began to explain his thoughts on the armored hero, "so iron man is like this guy in armor, so underneath the armor, he seems human, he looks very well equipped with technology that's very cool looking and a power source I've never seen before, and he's a bodyguard to an owner of a company called stark industries, named tony stark."

"I heard tony used to make weapons," explained Greg, having been reading about stark industries since his son watched iron man "until an incident with some terrorists got him captured and that he was able to escape with his life somehow, and when he got back, tony stopped making weapons since then."

"and finally, please explain Captain America to me," said garnet

"so, captain America is like a guy dressed in a red, white, and blue costume," said Steven "he seems to stand by his countries beliefs, cap seems to be a great leader, he's also strong, fast, and he's smart too! he carries around a shield he can throw like a frisbee, but it's also like a boomerang, it always comes back to him, and he never gives up."

"I heard this guy fought in world war II," said Greg, "and that he wasn't seen until decades later, and now he's fighting the good fight."

garnet looked thoughtful, she felt like she and other gems had met this man before when rose quartz was around, but hearing of his survival seemed surprising even for garnet

"steven, you may not believe this," said garnet "but, I believe we have met this man before."

"what do you mean?" asked steven, puzzled

"this Captain America," said garnet, "I think I barely remember meeting him years ago,"

"you do!?" gasped steven, his father sharing his surprise

"but, this comes as a great surprise to me hearing about this Captain America on the television," said garnet "we have not seen him for years..."

"can you tell us about it?" asked steven "please?"

"I shall, steven," nodded garnet, "it was over a decade ago...when we met a man named steve rogers..."

garnet told the whole story to steven and Greg of how the crystal gems met Captain America back in world war II, as steve rogers from the beginning

it was back when rose quartz existed when the crystal gems won the rebellion, but at a high cost, we met this frail yet determined human named steve rogers, who was protecting himself from another human, amethyst, pearl, and rose stepped in alongside another human who's name was Bucky Barnes, we each questioned rogers' decision to join the human military army, and why must humans fight amongst themselves,

"because I want to do what's right," answered the human. "I don't like bullies. I don't care where they come from."

rose and the rest of us commended this young man's spirit, and eventually, he trained in the military, but they considered him too skinny and too frail, but one human among the army saw potential in steve rogers, he told us his name was Dr. Abraham Erskine, the inventor of the super-soldier serum, a chemical which appeared to make steve better then he was before, rose and the others, including myself, sneaked into roger's personal room and joined on the conversation, and eventually witnessed the super-soldier serum's administration,

after what felt like an agonizing eternity, the project was successful, steve rogers looked better than he was before, stronger, faster, and seemingly more powerful than before, but after the project was successful, dr Abraham Erskine was murdered by a human from an organization called HYDRA, who were the main enemies of an event called world war II,

after steve rogers successfully received the super-soldier serum. However, the military finally accepted him and proved himself more than capable on the field, even after he began wearing a costume and a red, white. Blue shield that he throws but always comes back to him, and became known as Captain America rose, the others. I would assist every once in a while during the war. We had to deal with the corrupted gems. After all, Pearl seemed against the idea. Still, rose insisted we help in any way possible.

during the war, however, we saw steve rogers, who was now known as "Captain America," go through many hardships and sacrifices, including the loss of his best friend, Bucky Barnes, who had fallen from a snowy train in pursuit of HYDRA, we mourned steve's loss over his friend, but eventually, it was time for the final battle of the war

During the final battle, steve fought off against a red-headed human called the "red skull," who was the head of the HYDRA organization. The war ended with red skull's disappearance, and Captain America was lost. Still, the war ending showed that his sacrifice was not in vain...

"he was gone...?" asked steven but then got confused "wait, if he disappeared in world war II, then how is he on the TV?"

"Trust me, son," sighed Greg, knowing the horrible realities of war, not in person. However, "there's no such thing as a good war. War is very, very unkind."

"it is, Greg," nodded garnet, "but if what you told me is true, steven, and that Captain America is appearing on screen, this may indeed be a miracle."

"what do you mean garnet?" asked steven, curious

"steven, I had foreseen a vision once," said garnet that we would one day reunite with this human."

"Really!? we do!?" gasped steven with stars in his eyes

"yes, and you seem to believe in him, just as much as you believe in iron man," nodded garnet, adjusting her visor. "I have also foreseen us meeting iron man as well. I believe they can be a great help to us as well."

"How can we get their help?" asked steven

"I think we should start with iron man first, little buddy," said Greg, "and to do that, we need to make a call to his boss, tony stark."

"What should we do, dad?" asked steven

"first off, we don't have his number," said Greg, "but I think we can send out a letter to stark industries."

"and then have Jamie mail it, right?" said steven

"that's right, stchu ball," nodded Greg.

"then what are we waiting for!?" said steven, excited "let's get to work!"

"steven," said garnet, offering one last piece of advice, "please chose your words carefully. However, you write your message will determine whether or not iron man will join us."

"I will garnet, thank you!" cheered steven

"anytime, steven," smiled garnet as she adjusted her visor.

"come on, dad!" said steven "let's get to work!"

"you got it, stchu-ball!" said Greg, running with his son "wait up, hot rod!"

Once they arrived at his van inside a personal garage, Greg and steven got to work on writing a letter to stark industries. Steven learned from his many viewings of iron man and Captain America's news articles that the two heroes, including tony stark, resides in manhattan, new york. The young boy wrote about how he's watched iron man in action on the news and heard about stark industries, and he hopes they can meet tony stark and talk more about iron man helping the crystal gems. After a while, finally, the letter was ready to be mailed. It was now time to look for Jamie, the mailman of beach city. Steven found him at the nearby post office.

"Hi, Jamie!" greeted steven as he entered the building.

"oh! hi steven!" said Jamie "what are you doing here?"

"Jamie, I need a big favor from you!" said steven, holding out the letter in his hand "is there any way you can have the post office deliver this letter?"

"of course, where to, though?" asked Jamie, as he picked up steven's letter

"new york, manhattan," said steven

"new york?" exclaimed Jamie "that place is always lively!"

"It sure is!" said steven "this letter is for tony stark."

"tony stark?" exclaimed Jamie. "THE tony stark!?"

"yep! the very same!" said steven

"I'll make sure the post office gets this message across then! it must be important!" nodded James

"thank you, Jamie!" cheer steven as Jamie went right to work on delivering the message. "I sure hope that message gets through!"

Seeing his task completed, steven returned home to the crystal temple and met up with Greg. He was glad his son was able to get the letter sent to stark industries. They were both hoping they would soon get a response from tony stark himself, but for now, all they can do now is wait,

for this was only the beginning of a new adventure...