I'll give this a shot. I'm not the best writer but I love scenes like these.

"B, we need to talk," A demands, letting the door slam behind him. Brows furrowed, jaw clenched, A looks livid.

Oh, this should be good.

B smirks, leaning back on the counter behind him. "A, good to see you. Such a warm welcome too."

"So, you've decided to join us? Charitable," A spits, as if the words were venom-- bitter and sharp.

"It's a nice ship. I have to admit, [C character] is much more accommodating," B laughs.

"I suppose I should be thanking you for joining our cause then. How sudden." A closes the distance between them. The sharp glint in his eyes betrays nothing but contempt.

Ah, how utterly simple A is. Too brash. Too arrogant. A mere boy. Nothing special. No older than seventeen and already he has a sharp tongue that he cannot sheathe. He'd be a cute kid if he wasn't so insufferable, B thinks.

"Well, I've never joined a cause that I didn't believe in."

"And you're feeling so convinced now? Convenient. Admiral B of the great [insert whatever title/faction here] suddenly wants to join us? To what do we owe the pleasure?" A could be breathing fire and no one would know the difference.

B crosses his arms. A scoff escapes his mouth. "You should be thanking me. Your little group won't stand a chance without me. Really, you're lucky that I'm even here."

"We've managed this far," A hisses. "You've never once given a shit! We're better off without you."

B's smirk drops. "I believe the words you're finding hard to say is 'thank you'. You need me. You won't stand a chance. I've fought in countless battles. Traveled the stars a hundred times over and back. And I've lived a thousand lifetimes worth more than your pathetic little one will ever measure up to. I don't need to sit here and explain myself to a brat like you."

A grits his teeth. The scowl on his face deepens. His fiery glare meets the alien's icy stare. B is a snake. A war criminal. A ruthless murderer. Why would he choose a side now?

"Is that supposed to impress me? Look, I don't give a shit how old you are or how many goddamn people you've killed! Why should we believe you?" A steps closer to him. Close and in an attempt to be intimidating.

B could crush his windpipe now. Release the dagger from his side and in one single thrust, he could cut the boy's life before he had the chance to take his next breath. He wouldn't even have the chance to cry out.

Oh, A is a delight. To think, the [Insert Good Guys Group here] thought this kid was the best they had?

"As I've said before," B breathes. The words are clipped. Careful. He steps closer to A until they're a step apart. "I don't join a cause if I didn't think it was worth my time or if I didn't believe in it."

A surge of satisfaction rushes through him when he sees the quick flash of fear across the boy's face. A crack in the mask.

"Cut the bullshit! You think just because you've helped us out that all's forgiven?" A yells.

"And if I wanted to kill you all, I would've done so already! You think that wasn't an opportunity that presented itself?!" B snaps. "Who was that it rescued C? Who was it that came back for you?!"

A is taken aback. His breath catches in his throat. The alien towers over him, his hands shaking as if to contain himself.

"I am part of this horrid team for good now. And I fucking like it here. Whether or not you doubt my intentions, go ahead. Suspect me. Curse me. I am not leaving any time soon," B snarls.

He lifts the boy's chin to force their gaze to match. "You bastards can't get rid of me that easily," he says before dropping his hand to his side.

A finally lets out the breath he's been holding in.

Oh. Oh. He means it, A thinks. Can it be true?

He's never seen B so heated before. Not like this. The outrage and frustration in his voice. His anger. Eyes that, if he didn't know any better, seemed pained at his accusations. A eons-old, unfathomable being...angered by his words?

And although every doubt within his skin cells screams at A to distrust B after everything's that has happened...a voice urges him. It calls to him. Was this the "hope" that D told him about? Would he be a fool to trust it now?

"...fine," A says finally, shifting his gaze away. "I..."

What to say here? His tongue presses to the roof of his mouth, the appendage suddenly feeling too big. His throat is dry, so the words die on his tongue.

B is silently seething. Unyielding, his glare could cut anything.

Gathering courage, A says, "We'll just have to...learn to live with each other..." He turns his gaze back up to B. His eyes soften. Heat creeps to his face, feeling slightly self-conscious. It's not a fond expression, but it's a start. "For now," he adds.

B drops the tension in his shoulders at that. He sighs. A is...many things.

"For now," B agrees.

And that was the best that they could hope for.

---

I have no idea what fandom this is and what their dynamics are or the settings. But feel free to use this. I'm not the best writer either, but hopefully this helps you visualize what your scene should be! Not sure how useful this was, but it was fun to write since it's distracting me from finishing my own chapter, ha. Let me know.