“What happened to you, Tony?” An expression of despair is carved into Steve’s face as he kneels, bloody and bruised, at Iron Man’s feet. Tony is out of the suit, dressed casually with a single pistol in his hand. There are only three bullets left.
The Merchant of Death answers calmly as he lifts the gun barrel to the supersoldier’s head. “I’m tying up some loose ends, you could say.”
Steve chokes out, “Why? Why do this? I apologized; I’m sorry, I never meant to hurt you like this!”
Tony’s eyes are cold and unforgiving as he sets his jaw. “From the moment you met me you hurt me, no matter if you meant it or not.” There’s a resounding boom as he pulls the trigger.
One solid, silent second goes by, and then Steve slumps onto the floor, blood trickling from the hole in his forehead. He is dead before he hits the ground.
Two bullets left.
Next is Natasha. She regards him stiffly. There is no emotion on her face, only a hard mask to match Tony’s. “Natashalie,” Tony says, a mad glint in his eyes. He carefully clicks the next bullet in. “Never thought you’d die this way, huh?” Natasha juts her chin up, looking strong even with her ankles and wrists shackled.
“I always knew you weren’t a hero,” she tells him calmly, and the billionaire flinches violently before composing himself again. He is tense with anger.
“Neither are you.”
Natasha smiles slightly as she nods at him. “I don’t need to be a hero to be a good person. I have done all I can to redeem myself.” You have too much blood on your hands, Natashalie. See you in Hell.
The gun jerks back and the lips stop moving.
One bullet left.
Everyone is dead, except for Tony. He’s been saving this single special bullet for last. For a person he hates even more than the rest of the Avengers. He feels a detached sort of guilt as he sees Bruce’s body lying on the floor. He had injected the man with a sort of drug to stop the Hulk from emerging before he killed him. Bruce Banner had always been kind to him, had even seemed to believe in him. Once, Tony had believed in himself too. That was long ago, when he was still learning to walk and stop seeking his father for attention. (He hadn't been able to do the last one for a long time.)
A bullet for the one he hates most.
Tony smiles, a cold, cold smile, a smile filled with hatred and agony and broken relief. Then, without hesitation, he lifts the gun and shoots himself in the head.