"I'm telling you, you don't need it."

"And I'm telling you, without this, I'm not staying on. I won't lie; fighting alongside you guys was a good thing. But I...we need the assurance, Tony, I'm sorry."

Kara frowned as she walked into the kitchen for a snack, famined after a couple of hours of watching over a still unconscious Sue. Stark was there, still suited up for some reason, holding his helmet under his left arm. There was someone else; a shorter, haggard, graying man, wearing large glasses and ridiculously loose clothing. The newcomer was in the process of brewing tea at the stovetop, and startled a bit when she walked in.

Stark nodded at her. "Hey Kara. How are our guests?"

She pursed her lips. "Still down for the count. Vitals are strong, though." -she said, taking a seat at the island in the middle of the kitchen. "I don't think we've met yet." -she told the man.

He shook his head. "Not yet, no. I'm Doctor Bruce Banner."

"Kara Zor-El. Or Danvers, whichever works best in conversation." -she said, extending her hand. He shook it, gingerly.

"You're the Supergirl I've been hearing so much about, right?"

She nodded. "Did you come to check on the patients? I don't think they'll be violent, if that helps."

He cocked his head, confused. Stark snorted. "Bruce isn't that kind of doctor, Kara. That's what Helen Cho is flying in from Seoul for."

"I, uh...also wasn't talking about that kind of assurance. Not exactly worried about what people can do to me. Quite the opposite, in fact." -Banner explained. "I'm the Hulk."

Understanding dawned on Kara's expression. "Oh! I am so sorry. I guess I should've paid more attention in school, huh?" -she said, embarrassed. "Your name was probably on half the biology tests I've ever taken. I just never, y'know, connected it to your face."

Banner smiled, good-naturedly. "That's ok. I think most people haven't connected the dots yet on my relation to the Other Guy, either. Besides, I've been told my face is really hard to remember."

Kara hummed, mollified. "So, you're staying with us, then? Will you keep being an Avenger?"

"Well, that's really up to Tony." -he said. "I don't mean to impose, billionaire or not, but I do have certain...conditions I'd like him to meet."

"Like what?" -she asked, then coughed. "Er, if it's not rude to ask."

Banner shook his head. "Don't worry, you're fine."

Stark sighed. "He wants me to create a countermeasure to the Hulk. In case he goes rogue, he says. Which is kind of ridiculous, considering half the city owes their lives to the guy, myself included."

"It's still a very real possibility, and you should absolutely account for it. Even the Hulk agrees." -Banner declared, then amended, sheepish. "Well, for the most part."

Kara raised an eyebrow, picking up an apple from the fruit basket. "Wait, so...you and the Hulk are separate people?"

"It's a little more complicated than that." -he admitted. "It's like a Venn diagram; he and I are very different in the way we act and think, but there's still very distinctive elements we share. For example, I have legitimate anger management issues. The Hulk, on the other hand, can understand every bit as much science as I can." -he said, then shrugged, sheepish. "He just doesn't care much for any of it."

She pondered the information, munching on the apple. "I hope you don't mind me saying this, but it's kind of fascinating." -she said. "Don't get me wrong; I understand why you'd be apprehensive, but still."

"You're not afraid of him?" -he asked, a small but present twinkle in his eyes.

Kara shook her head. "Should I be?"

Banner hummed. "I'm not sure. They do say you're pretty strong. How strong are we talking, here?" -he asked, curiosity getting the better of him.

"I honestly couldn't tell you. I sort of...broke every test S.H.I.E.L.D. threw at me." -she said, blushing.

Tony smirked at Banner's awe-struck expression. "Kinda makes me want to see an arm-wrestling competition between you two. Maybe throw in Thor, if he ever shows up again."

"I bet he'd love that." -Banner said, fondly.

"I'm definitely up for it. It's really exciting to be around people I don't have to fear breaking." -Kara eagerly said.

Stark gave Banner an I told you so kind of look. "See? Even if the Hulk were to go a little off-script, and even if Thor was on the other side of the galaxy, we have Kara now. Nothing to fear, buddy."

Banner seemed to shrink a little. "I hope you don't mind me saying it, Kara, but I wouldn't leave it all to you." -he said. "You of all people should understand, Tony. Don't you have, like, forty modular armor designs ready to go, 'just in case' some hyper-specific problem arises? What if Supergirl can't shut the Hulk down quickly enough? What if he beats her? There has to be a contingency."

"I don't think that rabbit hole leads anywhere good, Bruce. Say I build this...'Hulkbuster' armor. Say you somehow manage to defeat Kara. I come in, kick your ass a bunch, then what?"

Banner grimaced, turning off the stove. "You do what you need to do to keep people safe."

Stark scoffed. "You're asking me to create a way to kill you, pal. That's not something I'll ever do, even if the Hulk turns on us."

Kara cleared her throat. "I think it's a good idea." -she said. "This 'Hulkbuster' concept, I mean. If I were ever made to do bad things, I'd want to be stopped, too."

Stark frowned at her. She held her hand up before he could protest, looking at Bruce. "However, there's really no need to talk about putting you down. Even the Hulk has his limits, right?"

Banner grumbled. "If he does, I don't know them."

"So, let's discover them. I can help, Doctor Banner. I don't mind sparring with your alter ego. Especially if it means you find some peace of mind."

The deceptively frail-looking man seemed to consider this, his eyebrows drawn together in thought. He poured himself a cup of tea, and offered another to each of them. Stark declined, but Kara accepted hers, immediately downing half of the scalding liquid.

"Okay." -Banner said, finally. "We'll design it together."

Stark grudgingly nodded. "I guess getting to say 'Iron Man smash!' is worth it."

She smiled. "This'll be fun, guys! You'll see!"

"You are entirely too happy about the idea of getting pummeled by the Hulk." -Stark said, amused. "I'll leave you two to whatever it is the strongest people on Earth do in their free time. I gotta go meet Obama about a thing."

He slipped on the helmet, which secured itself around his head, then walked out of the kitchen. Soon enough, the sound of jet boosters rumbled outside the Tower.

Banner spared a small smile for her gaping self. "So, what does the strongest person on the planet do in her free time?"

Kara snorted. "I don't know about you, but I eat. Rao, I'm starving."

He laughed. "I definitely get what you mean. Brunch?"

"Definitely brunch."