Author's Note: For simple continuity, I've kept the Avengers in the film verse. JLA is in a generic non-specified verse, perhaps animated series, since they have no live action currently. My Bruce is NOT based off the Bale's portrayal in the Nolan films, I'm going classic comics/animated Batman.
Also, in this made-up continuity, the Justice League are already an existing team, they were just very underground. After seeing the success of a superhero team like the Avengers, they have gone public. I did this as the Justice League existed before the Avengers in comic book continuity.
If this fic is well received, it will become a series.

Bruce was going to kill Clark for this match-up.

Of all of the Avengers to work with, he was stuck working with the one he had tried to avoid working with at all costs. Anthony Edward Stark, or as he was also known, Iron Man. Bruce had known of Tony Stark for some time now. How could he not? Stark seemed to go to all ends to make sure the entire universe knew who he was. And he had took it one step further when he recently revealed that he was Iron Man, which Bruce saw as incredibly stupid. Perhaps because Bruce went to all lengths to keep his identity and dual lifestyle a secret. He saw this as more of another show of attention for Stark.

Though Bruce would admit, the other had proved his worth as a hero (though still only somewhat to the Dark Knight), in the recent battle that took place in New York City. Though, Bruce still was not completely sold on Stark as a hero, he had earned somewhat respect for the other man. Not enough to work with him, but it seemed that he was to have no say on that. For some reason, his team had elected Clark to be the one to pick the super pairs, along with Captain America from the Avengers. He wondered if Clark paired him with Stark to spite him. He wouldn't put it completely past the Man of Steel. Though, perhaps Bruce's negative feelings toward his partnership with Tony were playing a role, and channeling said emotions toward Clark.

Then again, he often had emotions like this toward everyone.

Either way, Stark was supposed to arrive to Gotham to work alongside Bruce. Tonight was their first night practicing the partnership, and Bruce was completely dreading it. He currently sat alone in the Batcave, busy on the computer. He was trying to find out as much information as he could on Tony's various Iron Man suits before the other arrived. He still was not in complete trust of the other man, although the conditions would require him to reveal his identity to the other. But either way, he wanted to know what he was getting into, just in case something went wrong.

"Sir, Master Stark has arrived."

Bruce peered from the corner of his eye as he heard Alfred walk in and announce his guest's arrival. He closed all of the open pages he had on his computrer, not wanting the other to know what he had been doing. "Alright, send him in." Bruce muttered, wondering if he would regret that decision in the very near future.

"So, if this is a Batcave, where are the bats?" Tony Stark asked obnoxiously, as Alfred led him in.

"I believe Master Bruce may acquaint you with his baseball one, considering his current emotional and excitement state." Alfred remarked, witty as usual.

"Thank you, Alfred." Bruce grumbled in an attmept to dismiss him. Alfred took this as a cue to leave the two men alone. Bruce got up from his chair, walking over to the other, who was already clad in his suit of iron and carrying the helmet for now. Bruce recognized said suit from the brief research he did, relieved the other did not surprise him with a new and foreign model.

"Mister Stark." Bruce greeted solemnly, extending his gloved hand out for a state.

"So. Bruce Wayne is Batman, huh?" Tony, of course, knew just as much about Bruce Wayne. How could he not? Bruce Wayne was in headlines and tabloids almost as much as him. Though, the Batman thing did come as a bit of a shock to Tony. He had not been anticipating that at all. Seems like he wasn't the only one who thought of the 'billionaire playboy' as a cover-up for a superhero alter ego, though it was no longer a cover-up for Tony.

"Yes, and unlike you, I'd like to keep it a secret. So do me a favor and keep your mouth shut." Bruce warned darkly.

"Ouch, talk about ice cold." Tony shifted his gaze away from Bruce, looking around the Batcave. "Well, this place seems pretty state of the art. Pretty impressive, Bruce."

"Thank you."

"Of course, it's not nearly as impressive as Stark Tower, my own creation, which has-"

"I didn't invite you here for a bragging competition, this is team business." Though Bruce had quite a few brags up his sleeve that he could easily use to counter. "You're supposed to work alongside me tonight, in my hometown. I normally patrol with Robin at this time, you can fill in for him." Bruce said, more or less belittling Tony to the status of his sidekick.

"Robin? You run around with a bird?" Tony asked.

"Robin is my side-kick, my ward." Bruce growled.

"Well, that makes more sense." Tony replied. "But seriously, don't think I'll be playing sidekick to some rich kid with fancy toys."

"And don't think I'll be playing side-kick to some rich kid playing dress-up in a suit of armor." Bruce countered.

"At least I'm not playing dress-up in tights and a cape."

"…let's go, it's getting late." Bruce growled, putting on his cowl, looking away as he noticed a smug smirk of satisfaction form on Tony Stark's face. What he would give to punch that man. He shook his head, wishing tonight would be over already. "Alright, I'll take the Batmobile into Gotham. From what I understand, you can fly in that suit, so just follow behind me."

"I want to ride in your car." Tony decided.

"Why do you need to ride in my car, you have those jets for a reason!" Bruce questioned, irritation clear and obvious in his tone.

"Well, yeah, but from what I know, this 'Batmobile' is a top-notch supercar. Rumour has it that it's your best toy, I want to see it in action." Tony explained.

"…call my equipment toys again and I'll show you what they can really do." Bruce said darkly, before approaching the sleek black car, and slipping into the passenger seat. "Just get in and shut up. Rule number one of the Batmobile - no talking."

"Well, looks like I'm breaking that rule." Tony replied, causing Bruce to clench his teeth and bite back the nerve to say something rude. He kept telling himself this was for the team, for the greater good of the world. Clark was still going to get it later.

"Buckle up." He told Tony, noting the other did not. He was used to Dick, who always buckled up and generally behaved.

"Oh yes, Mommy." Tony joked, as he climbed in the car, not bothering to buckle up. Bruce merely clenched wheel tighter, as a means to control his already short fuse. Once the other got in the car, Bruce started up the engine, opening the door to the Batcave and speeding off. He watched Tony from the corner of his eye though, noting the other inspecting every little aspect of his car.

"Hey, you wanna know how you can make this car better?" Tony asked.

"What happened to no talking?" Bruce mumbled.

"Well, what I think you should do is replace the-"

"It's fine."

"You didn't let me finish, because if you took out-"

"This car has catapulting seats - do you want me to show you how the passenger one works?" Bruce warned the other.

"Alright, alright!" Tony exclaimed, shaking his head a bit. "Would have thought a party guy like you wouldn't be so…rigid. To think, I always wanted to party with you."

"You already did."

"What, really?"

"Yes."

"When?"

"I don't know, we were at the same party last year. All I know is that I left to get a drink, and the girl I was talking to had her tongue down your throat when I got back."

"Was she blonde?"

"No, red-head."

"What color was her dress?"

"Are we really having this conversation right now?"

"Hey, you're the one who brought it up, I'm just the one-"

"Quiet!" Bruce snapped out of nowhere, looking down to one of the GPS screens that flashed a notification at him. "Robbers. Eight blocks away." He said, before increasing the speed he was driving.

"Guess speed limits don't apply, huh?" Tony said, stumbling back as he did not put on his seatbelt.

"I told you to buckle up for a reason." Bruce grumbled, as he made a sharp turn. "We wouldn't even have this problem or annoyance if you had just flown like I said." This was almost as bad as the time he let Wally ride in his car. Fastest man alive, yet he insisted on riding in the Batmobile and bringing in mounds of fast food, which created trash. And even then, Bruce would rather have Wally here than Tony - that was saying something.

"Well, seems like everything is my fault tonight. Guess the great Batman can never mess up. Nope, you're just flawless, aren't you?" Tony asked, rolling his eyes.

"We don't have time for this." Bruce pulled the Batmobile aside and put it in park. He jumped out of the car. "I can stop these robbers no problem. No point in us both going. You stay here and watch the car." Bruce took out his grapple gun, and flung off with it the force it created.

"Wait!" Tony called out and sighed. "And just when I thought I was getting good at teamwork." Tony didn't think there could be anyone less willing to work and cooperate with others until he started working with Bruce Wayne. Was he like this with everyone? Or was it just the fact that the Bat did not want to work with him? He said they didn't have time for bragging competitions or ego battles, yet Bruce seemed to be the one fueling almost all of them. Either way, Tony knew he was not just going to sit back. Whether they liked it or not, they were a team tonight. And teams stuck together. Tony grabbed his helmet and put it on. He looked up, spotting the black cape go by on the rooftop of a near building. Bruce must be chasing them up there. Using the jet power of his armour, Tony started to fly up. But he stopped as he saw something falling from the sky. Rather someone.

It seemed Bruce had been overconfident. Sure, robbers were robbers and bottom of the barrel criminals, but they could be surprising every now and then. And in Bruce's overconfidence and underestimation, he slipped off the roof. Tony acted quickly and caught the Dark Knight in his arms, as the other struggled to find his grapple gun.

"Gotta say, you're the ugliest damsel in distress I've ever saved." Tony told the other.

"Will you put me down!" Bruce exclaimed, obviously not happy with having to be saved. He knew he could have saved himself. His grapple gun, he could have used that and then-…ah, what was the point, they had gotten away anyway. Tony settled on the rooftop though, Bruce immediately getting out of the other's arms. He looked around. "They couldn't have gotten far. If I take the Batmobile, I can find them and-"

"Alright, look, enough with this "I" and "Me" stuff, Batman." Tony did make sure not to say Bruce, as the other valued his secret identity. "I've read about your Justice League of America - you work as a team, a team where everyone is equal and you fight for the greater good of the world and justice. Do you really think you're making the Justice League proud tonight?"

Bruce said nothing at this. He refused to admit that Tony's argument was right, and that maybe he did let his own ego get in the way tonight.

"I don't care if you don't like me, Bruce, that's not why I'm here. I'm here for my team, your here for yours. Let's work together, stop those scumbags, have a drink and call it a night." Tony extended a hand for a shake. "Deal?"

Bruce eyed the other's hand for a long moment, looking from it to the other's mask. He slipped his gloved hand into Tony's armoured one. "Alright…deal." He agreed. This handshake was much more sincere and meaningful than their initial meeting one had been. It was no longer an ego struggle between the two men - it seemed as though they were able to find a common ground. The good of the world, and their teams.

"Good, now let's go kick some ass. No way are Iron Man and Batman going to be shown up by some low-class robbers." Tony said, as he flew off to pursue.

Bruce smirked. "Well, I don't know about Iron Man, but I know Batman won't stand for that." He followed in a sprint, used to keeping up with flying teammates. It didn't matter how or when he got there. What mattered was that they were going to fight together and win together.

—-

"Your move."

"Don't rush me, I'm thinking."

"I can feel my hair turning grey as I wait, come on."

A chessboard separated the two superheroes, both still clad in costume. Tony leaned back enjoying his drink, as Bruce contemplated his next move. The 11 o'clock news played in the background on the large screen, though neither man paid much attention to it. Bruce lifted his own chess piece, placing it down.

"Checkmate." He announce proudly with a smug smirk. Tony nearly spit out his drink at this.

"What! How? No way, there's no way." Tony studied the board, though it was completely obvious that Bruce had won fair and square. Now he was the one doing the underestimating. "Alright, best two out of three?"

"Deal." Bruce said, as he started to reset his side of the board, Tony doing the same. As this was being done, the noise from the TV became clearer and more obvious.

"…and in recent news, billionaire Tony Stark's Iron Man was spotted working alongside Gotham's own Dark Knight tonight. The two apprehended a pair of robbers who stole more than twenty thousand dollars from Gotham's bank. No comment has been made by Stark or Batman on the partnership tonight. Could this be a coalition of the recently revealed Justice League of America and the Avengers? Only time will tell. In other news, there was…"

"Looks like we made a pretty good team." Tony commented, as the board was set up.

"We were okay." Bruce decided.

"Maybe we can hang out like this more often." Tony suggested.

"Don't push it." Bruce said, though he did offer the tiniest of smiles to the other man. Tony laughed in response.

"Your move."

((Ending scene with chess was inspired by an image of Tony and Bruce playing chess, though I am unsure of the original artist. I hope you all enjoyed this fic, I apologize if it was a bit sloppy and choppy.

Any feedback/criticism would be appreciated. Thanks!))