So this is in some strange AU (still with heroes) where Bruce's mother and her husband are scientists. Tony Stark came to work at their lab and of course had a one night stand with the pretty female scientist because come on, he's Tony Stark.
Anyway, after Tony leaves and goes back to doing what Tony Stark does Maria Banner realizes she's pregnant. Brian Banner knows it couldn't have been him and he resents the child for that. Brian decides that if it can't be his son then Tony can't have him either, so he convinces his wife that Tony would be mad about the child and not to tell him. Brian Banner wasn't always the best of husbands so Maria was unsure about his fathering skills, but he seemed all right from her point of view.
Brian was careful with his abusing of the little 'Stark Spawn.' Sadly, Dr. Brian Banner killed his wife in the lab after a particularly heated argument involving placing Bruce into an orphanage when he was six. Maria Banner's death was blamed on an accident in the lab and he got off scott free.
Brian Banner planned to kill six year old Bruce in the same manor, but when he exposed the boy to the gamma radiation Bruce's body did something a bit strange. He turned into a big green thing, a big Hulking monster. The creature immediately attempted to escape from his confines and broke out of the lab, accidently stirred up a little chaos, and went into the woods surrounding the town. Brian found little Bruce, shrunk back to normal in the woods and took him back to the lab, thrilled with what he had created.
Brian tried to harness this Hulk as he called him, but every time he managed to bring the Hulk out he simply ran farther and farther away, causing more headlines and more publicity. Finally, one day the creature killed Brian Banner accidently when he broke through a window and the glass injured him and Brian bled out before help came.
When he shrunk back down to himself, eight year old Bruce Banner was terrified and was found crying in the woods by police who had been looking for him since they found his 'father's' body.
The child was taken to the station and his birth certificate was found and his real father, Tony Stark, was called. Tony, doing the math realized that this child could really be his and had immediately demanded a paternity test. Being Tony Stark this took all of five hours and by that night someone explained to Bruce who his real dad was and that Tony was going to take him tomorrow.
The next day, Bruce had boarded a private plane with his meager belongings to meet his father and had been skittish and shy and hadn't said anything, even if his father wouldn't stop talking about random things like where he was going to live or what he was going to do now and stuff. Finally they had reached an awkward silence that was broken when Tony had gotten to his mansion at ten at night, showed the kid to his room, next to his, and left him to his own devices after explain JARVIS is the AI and can get him things and direct him around and stuff.
Tony immediately goes down into his lab and blows off some steam with rock music and machines. Things he understands.
Alright! Enough Backstory!
Bruce sat down in the big room Mr. Stark had led him into. It was too big for him and he should have told Mr. Stark that, but what if he made him mad? The little boy did not want his new father to be like his last one. Well, the last one wasn't really his dad was he? And this one was a superhero. With his glowing thing and everything. Bruce had seen it. Superheroes were always good, right?
The boy looked around the large, modern looking room as he contemplated these things, with its fancy off white color scheme, and minimalist furniture that just made him feel even smaller than he already was. Bruce didn't fit with the cleanliness of the room in in his baggy jeans, a decrepit T-shirt that had once been blue, and hair that hadn't been washed since four days ago when this mess started. He left his faded backpack that had at one point been some bright primary color and held everything he had been allowed to take with him, on the floor next to the bed that could probably fit at least six of him.
The brown eyed boy took his scruffy grey sneakers off, who knew what color they had started out as, and placed them on the floor next to the white rug beside the bed so as not to get dirt on it. He decided to take his socks with holes on the balls of the feet off too, just to be safe. Why was everything so light and clean in here anyway? Didn't Mr. Stark know that this was supposed to be a kid's room? Dad- no not dad- always said kids were messy and a bother. Maybe Mr. Stark was going to move him soon?
Stark man good. A voice said in the back of his mind. A voice that Bruce had learned to trust since he first heard it two years ago. Sleep now. Think in morning.
His eyes started to close and Bruce shook himself awake. The other guy was right, Bruce should sleep. Spotting the door that Mr. Stark had said lead to the bathroom, he picked up his backpack and walked over, regretting leaving his shoes and socks by the bed as the tile of the floor was freezing on his bare feet. Thankfully, the bathroom had matching white rugs that were soft and warm to stand on.
Bruce quickly used the bathroom and changed out of his worn jeans and faded T-shirt and into an overlarge softer T-shirt. Not knowing what to do with the soiled cloths, he simply put them back in his bag. He managed to find his blue toothbrush that he had gotten last time he went to the dentist, and squirted on the toothpaste that he saw on the counter. The boy sung the alphabet song twice just like his mother had taught him before she died, then rinsed off the brush and left in on the counter. A wet toothbrush would be gross to put in with all his stuff.
Bracing himself for the walk back on the unforgiving tile, he hefted his bag back on his shoulder. Bruce, in a brave moment, started the walk and was surprised to find the tile was now warm.
"What?" he whispered quietly, the first true words he had spoken since getting on the plane this morning with Mr. Stark. He took another step into the room to see if the whole floor was like that now.
"The tile has been heated to a warmer temperature, sir," a calm British voice from the speakers explained. That must was JARVIS, the AI that ran Mr. Stark's house.
A small smile flitted across the little boys face as he easily made his way back over to the bed, pulling out a small 'well-loved' teddy bear from the front pouch of the bag and depositing it on the floor while he put the bear on the bed. "Oh, um, thanks." After all, it did seem rude not to say something back.
"My pleasure. I can set the floor to be always be this temperature." The disembodied voice said a transparent screen suddenly appeared in the air, showing the temperature and other statistics of the room. The AI seemed to be able to tell Bruce was smiling when the statistic on the screen suddenly changed and then the screen disappeared again. "Is there anything else you require?"
Bruce started to decline but as he looked around for a light switch, he realized he couldn't find one. "Um, how do you turn the lights off?"
"I will do that for you if you get into bed, sir."
Yes, sleep good. Sleep time.
"Okay," the brown eyed boy said, and even he didn't know which one he was responding to. Maybe both, he decided as he pulled up the warm, off-white, covers around himself and settled into the comfortable mattress and the amazing pillows. He was asleep before the AI could turn the lights fully off.
Unfortunately, the boy woke up panting hours too early from a horrific nightmare. His fluffy brown hair was in disarray and his brown eyes were wide as he curled himself into a ball around his bear and tried to will the strange messed up world his nightmare had left him in.
All he could remember was his dad-no not his dad- putting him in a cage and poking him with sharp things, encouraging him to change. He wanted Bruce to show him the monster, but the other guy wasn't a monster, why didn't he get that! Bruce shoved his face into his pillow. But what if the other guy was a monster because he helped Bruce? If Bruce is bad, surely whoever helps him must be bad?
Stop thinking. Gone now. Safe.
He was right; Bruce thought as he breathed. It didn't matter anymore. He was gone. They were safe here in Mr. Stark's mansion that was too big and clean and fancy.
Suddenly a door opened into his room and the little boy looked up as dim light filtered in from the hallway, outlining Mr. Stark.
"Hey kid, what's up," he asked, yawning. Mr. Stark looked really different in sweat pants and a T-shirt than he did in his fancy clothes with his hair slicked back. His chest had the faint glow that he had seen in the Iron Man suit on TV once or twice. Bruce had to admit that he liked him better this way.
"N-nothing," Bruce answered quietly. His old dad had never come in to see him at night. This was new and different and the boy didn't know how to deal with this. "I didn't mean to wake you, Mr. Stark."
But Mr. Stark moved in closer and sat on the edge of his bed, making Bruce shy away a bit. "I said you could call me Tony, kid," Mr. Stark sighed as he ran a hand through his already disheveled hair. When Bruce didn't make any noises of hearing him, he continued. "Nightmare?"
Bruce nodded a little bit, but didn't say anything. Was he supposed to say anything? He didn't think so.
"You could talk about it if you want to," Mr. Stark pushed, scotching a little closer to the boy who didn't back away. "I can be a good listener."
Bruce shook his head vigorously and hugged his bear a little tighter to his chest.
"Yeah, sometimes I don't like sharing my nightmares either, kid," Mr. Stark said as he looked down at Bruce, who looked rather shocked.
"You, you get nightmares too?" he asked curiously, actually looking up at the man on his bed. His dad- old dad- said they were for kids when he mentioned them once. Who knew the Tony Stark had them too?
Tony is good man. Nice. Safe.
"Yeah," Mr. Stark replied nodding, and at first Bruce thought he was responding to the other guy, but then he remembered his questions. "And sometimes I can't sleep anymore, so I have to go down to my lab or something."
"What are yours about?" Bruce asked quietly, still a little stunned that Mr. Stark got nightmares too, and he leaned a little bit closer.
Mr. Stark looked down at his son and the same shade of brown eyes met. Suddenly, Mr. Stark put his arm around the boy and pulled him to his side. Bruce was surprised at first, but quickly he leaned into it. His mother used to do that when he was scared. Maybe Mr. Stark needed the comfort.
"Do you know how I became Ironman?" Bruce shook his head against his side.
"Well, I was taken by these, um, bad guys who wanted me to make weapons for them. But when I was taken I was in an explosion that got shards of metal in my blood stream. So there was this doctor who put in this thing in my chest to keep the metal away from my heart."
"A magnet?" Bruce asked curiously. He wouldn't have interrupted if it had been his first father but the other guy seemed to like Mr. Stark and he was nice so far.
Mr. Stark smiled down in surprise. "Yeah, kid, it was an electro magnet. You must get your brains from me," he said smirking. Bruce's eyes widened. He was the son of Mr. Stark the smartest man in the whole wide world, what if he didn't like him because he wasn't smart enough?
"Or who knows, maybe you'll be like Maria and be interested in Gamma radiation or something," Mr. Stark continued. "Or maybe you'll blow everyone away and be an architect or something. Don't be afraid to be different, kid."
Bruce nodded happily.
See? Safe. Nice.
"What happened next, Mr. Stark?"
"Tony," he enunciated, Bruce nodded, but Tony insisted. "You can call me whatever kind of title you want. If you want to call me dad go crazy, but if you're going to use my name at least use my first, okay?"
"Okay, Tony," Bruce agreed, wanting to hear more of the story now. Old-dad never told him stories.
"Well, they wanted to hurt people with the weapons, so I didn't want to build them, so they had to make me do it. So I told them I would, but made the first Iron Man suit instead. Then I broke out with it, but I still have nightmares about that place."
"Oh," Bruce said slowly looking at the glowing piece of metal in Tony's chest that was next to his face. "What's this then?" He pointed.
"That, little doctor, is an arc reactor. It basically does the same thing as the electromagnet but a lot more powerfully," Tony explained while tapping it. "You can touch it. It's not hot or anything."
Bruce reached out and touched it for a second, just a second, than he wanted to touch it more because it felt so weird. "That's cool."
"So what are yours about, Doc?" Tony asked and Bruce had to admit that the nickname made him feel a bit better. Old-dad never had a nickname for him. Tony squeezed his arm a bit tighter around Bruce as if encouraging him to go on.
Safe. Tell Tony. Protect us.
"You can't tell anyone," the little boy warned as he pulled his legs to himself and wrapped his arm around his legs and rested his chin on his knees.
"They're about the other guy," Bruce said quietly then looked up scared as if his father would turn on him.
Tony looked a little confused. "What other guy?"
Bruce's distress grew.
"You've seen him," Bruce urged. Hulk had been in the news. Hulk had been everywhere because people had no idea what to do with it. "Oh, JARVIS can you put up yesterday's news from my town."
"Of course, sir." And suddenly a wall converted into a screen that showed all the headlines on the Hulk. Bruce's eyes started to burn in the way that only happens when someone is holding back tears. What if he was just a freak?
Tony read them fast and looked down at Bruce. "Is it because he killed your dad?" But Bruce shook his head the tears making their way down further.
"He… he did something to me," Bruce sobbed. Then continued before Tony could interrupt. "Not him," the boy gestured to the screens with his head. "My fake dad did," he managed to get out.
"What did he do?" Tony's smile face seemed frozen as if dreading what the eight year old would say.
"I, I was in his lab. He to-told me he wanted m-me to watch him d-do something. But then everything hurt and he was there." The boy nodded towards the screens again.
"So David Banner created the Hulk," Tony asked slowly. "Where is the hulk now?"
"In my head," Bruce said sadly. "I don't know what happened, but now he's in me. And whenever he thinks we're in danger he takes over and brings us away. He just tries to get away and not hurt anyone, but he- my fake dad- was really really awful and finally he just snapped. He's a l-lot stronger than I am." Bruce did not look up at his new-dad, afraid of rejection. "I know I'm a freak, bu-but he just wants to protect us!"
Tony squeezed Bruce tightly against his side and ran his hand through his hair, which was surprisingly soft. "You're not a freak, Bruce," his new-dad reassured. "You're just special."
"Really?" Bruce asked in amazement as he looked up at his dad.
"Promise," he said as he wiped the tears off of his son's face gently.
"Can you talk to him? Like right now?"
Bruce nodded. "He says you're nice, and safe."
Let Hulk out. Hulk talk.
"He wants to talk to you," Bruce translated.
"How about in the morning?" Tony said yawning. "I think he would agree when I say you need sleep, Doc."
Tony smart. Sleep good.
Bruce giggled a bit. "He says sleeping is good." Tony smiled and made to get up, but Bruce grabbed his hand. "Maybe you could stay?" the boy says hesitantly. "We could keep the nightmares away from each other?"
Tony smiled and got back in the bed this time lying down and pulled his son down next to him. "Good idea, Doc. We'll be perfectly safe tonight."