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Tony is well aware he’s a bad person. Well...not a good person, at least. He knew it before the Avengers, and he’s even more painfully aware of it now that he’s part of this thing they’ve become, not a team and not the Avengers, but something strong and solid and freakishly broken that vaguely resembles a family if you tilt your head and squint at it. He’s not sure he fits, but he knows he does, because nobody’s kicked him out yet.
Sure, they’re all crashing at his place, but that’s not the point.
The point is, he’s got a thing for Bruce Banner. He’s not even sure what it is: mancrush, bromance, a new best friend, a fresh resurgence of the sexual curiosity that got him through college without blowing up anything too important, but Tony can’t get the scrawny little badass the hell out of his head. He can’t stop hovering, can’t stop poking, can’t stop trying to dismantle him in the privacy of his own mind, piece by piece...and then there’s the Hulk, which just adds a whole new layer of interesting.
Bruce Banner is a machine, and Tony likes machines. They have parts and cogs and cylinders. They have all of these bright, shiny little components that, when you put them together, make something as close to alive as you can get without actually having kids. You can make cars that fly down the highway at one-sixty, planes that actually do fly, missiles and superhero suits and tiny glowing blue cylinders that can power a city for a week...
Bruce is big and complex, and all of the parts that make him up are shiny. Tony knows he’s kind of a magpie that way, and he could give a rat’s ass. He likes his toys, and Bruce...well, Bruce is both toy and playmate. He’s this strange sort of...level, the air bubble drifting this way and that until he reaches an equilibrium, and Tony knows he’s doing it right, whatever it is at the time. He’s as much an instrument as he is a sounding board, a companion, another mind to analyze data and reach a conclusion. With Bruce’s help, Tony’s done some amazing things he never could on his own. Sure, mostly because Tony’s had to brush up on his biophysics and advanced nuclear chemistry just to be able to talk with him intelligently (and maybe a little general medicine so he could try to get Bruce to open up about his time in Calcutta), but again: that’s a bonus. Bruce pushes Tony to be more, not just to behave.
Bruce actually thinks Tony is brilliant. Tony. This man who ought to be a Nobel laureate, curing cancer and unlocking the secrets of the universe instead of running from the US government, thinks Tony Stark is brilliant. There’s nothing good about that part, no. That’s a chore, a responsibility, and Tony’s very shaky when it comes to taking responsibility. The repeated screw-ups inherent in being Iron Man are proof of that, proof that Tony isn’t worth the time and the trial of putting up with his crap.
It’s also wrong, because Tony isn’t brilliant. Not compared to the man who texted him twenty minutes ago, now standing in the corner of Tony’s workshop (which JARVIS allowed him to break into), staring at him like a scared rabbit while he, in turn, stared at the holographic monitor in his workshop, displaying a projection of the ARC reactor in his chest.
“You hacked my private server for this?” he breathed. Slowly circling the projection, Tony reflexively started doing the math in his head as he stared at the readouts and figures, as well as the tiny piece of circuitry at the base of the reactor, built into the core above the connector that basically plugged the thing directly into his heart.
Bruce nodded, wringing his hands restlessly. “Yeah...like I said, it’s still theoretical, but I needed access to the energy outputs and the biometric readouts before I could come up with a composite. I also had to see the breakdown of the reactor so I could find out just where a component like this could possibly fit in...”
Tony continued to circle the monitor, still calculating. The math worked, and as he reached out and exploded the view of the reactor, plucking that little piece of light free and zooming in, he took in the mockup of silicon and metal and glass, staring at the figures that popped up in greater detail.
“I’m not an engineer.” Bruce continued. “I mean...I don’t know if this is even possible in reality? But I think it could be. W-with enough time, with enough--”
“Banner, stop apologizing.” Tony murmured, eyes wide as he began to break the circuit apart and look inside its construction. “You do not apologize when you are Van Gogh and you’ve just painted Starry Starry Night, this is breathtaking. I’m not even sure I completely understand what this is for, but it’s gorgeous.”
When he glanced to the side, Bruce’s features were deeply etched with confusion. “Really?”
“Seriously, I don’t bullshit when it comes to building things.” He replied flatly, honestly as he returned to the jewel in front of him. As far as he could tell, it was a miniaturized processor, designed to run on the power of the reactor, while at the same time changing the reactor’s function. It created an independent electrical charge, contained organic components, used portions of the reactor’s output to actually change molecular structure...it was a microscopic factory of some kind.
“What’s it making?” Tony finally asked. “This processor, what’s it for?”
Bruce blinked, as if surprised, and paused to put his glasses back on so he could better see the projection (and Tony wasn’t even going to think about how that was kind of cute: Bruce being nerdy and fussing with his glasses).
“Oh! It’s a converter, actually.” He explained, manipulating the projection as he spoke and losing some of that frightened, nervous twitchiness as he fell back on something comfortable. “When you asked me to help you replace the Mark III chestpiece last week--”
“You did this in a week?!”
Bruce stared at him blankly for a moment. “Well...yeah.”
Tony just gaped...then smiled, folding his arms as he nodded to him. “G’head.”
Looking a little unsure, Bruce continued with his impromptu presentation. “There’s an excess buildup of plasmic discharge in the reactor cavity, I damn near couldn’t get the thing connected. I’ve also noticed your intermittent bouts of hypoglycemia. The vibranium may not be a toxic power source, but it’s affecting your metabolism, it’s speeding it up. I hypothesized that the vibranium core could possibly correct its own problem, so I sketched up this thing. These vials contain organic proteins, and with an electric charge, can alter the molecular structure of the discharge. If we can build a vent into the reactor cavity, the excess discharge can be released into your bloodstream.”
“Wouldn’t that be...kinda bad?”
“No...no, sorry. The product of the converter is a synthetic glucose substitute. It’ll prevent your metabolism from crashing on itself.” Bruce added hastily. “Solves the issue with elevated metabolism.”
Tony turned from Bruce to the projection and back to Bruce again.
“Like I said...gorgeous.” he replied, and for just a second as he met the other man’s gaze, he wasn’t precisely sure he was talking about the converter anymore.
Bruce smiled at that, and Tony went from being unsure to absolutely sure.
“I just don’t understand why.” Tony went on, shaking himself back to reality. “It’s useful, it’s...fantastic, but why go to all this trouble? I’d have gotten there eventually.”
“Not without a degree in biophysics, I don’t care how good you fake it.” Bruce quipped, and Tony let him have the dig. God knew he spent enough time poking the guy, it was nice when he poked back.
“I wanted you to have...this.” he continued, rubbing the back of his neck with a strange expression somewhere between sheepish and pleased. “The thing needs work, lots of it. It’s purely theoretical at this point, so we’ll have to work on the numbers, draft up a new schematic based on any changes...machine a prototype.” He paused, meeting Tony’s gaze.
“I wanted to give you something. To say thanks...for letting me stay here, for having my back...maybe even for telling the team about the Other Guy’s thing for mixed nuts.” He explained, making Tony snort with a suppressed chuckle. “But what do you get the guy who has or can buy everything, you know? It’s a new project, a new idea. And soon, it’ll be a new piece of equipment to play with.”
“A new machine.” Tony agreed softly, turning back to the projector. Reaching out, he collapsed the schematic and plucked the ARC loose, complete with the new converter, and smiled.
“And I love machines.” He went on, staring into the core of the idea that came out of Bruce Banner’s head.
Bruce Banner, who thinks Tony is brilliant. Even if he’s not.
He tries, though, Tony really tries to live up to it. Iron Man, he can fuck that up all day long, there’s five other Avengers to step in, but being the man Bruce believes he is, believes he can be? Being the man who deserves gifts like this, just because he learned how to make nice with the big green half of Bruce’s lizard brain?
No question, no room for argument: Tony can and will not fuck that up.