Batman vs Iron Man is a Marvel Crossover involving Batman. This story was written by Sport Shouting .
Sitting in a Wayne Enterprises meeting, an unknown caller tries to Skype Bruce Wayne. His name is Tony Stark and asks to meet Bruce at Stark Tower . Walking there, Whiplash attacks Bruce. Running into an alley and opening the briefcase he brought, he puts on the Batsuit and defeats Whiplash at the exact moment Iron Man (with the mask up) flies down.
"Bruce! Nice to see you." Tony Stark says
"How did you-" Bruce replies
"How did I know? A: you came to the place I invited you too and B: you are one of the only people who can afford the tech like that. I'd know" Stark interrupts.
They sit down, hang out and get drunk at night. Accidentally spilling out they're life stories, they crash in Stark Tower and word gets out that they are together, which attracts the attention of assassins. Deadshot and Bullseye meet up and decide to compete for the kills.
Ironically, they both arrive at Stark Tower at the same time where Bruce and Tony are sparring. A gunshot is then heard and Pepper Potts falls to the floor bleeding. Tony gives her medical attention, calls Jarvis for help and Bruce gets his suit on. The two assassins enter the room right after Pepper passes away from the gunshot. Enraged, Tony gets a suit and dives through the window with Deadshot in his arms. He crushes onto the ground, crushing the spine of Floyd Lawton, killing him. Bruce and Tony shake hands after the funeral agreeing that "they'd always be there".
That leaves Batman and Bullseye on the top of Stark Tower. Bullseye is without a gun, so he pulls a switchblade. Batman easily wins the fight and Bullseye is placed into S.H.I.E.L.D custody. Bruce goes to Pepper's funeral. After the funeral, Bruce and Tony shake hands, saying "they'll always be there".