A/N: This is my first attempt at RvB fic. Many, many thanks go to skywalker05 for helping me out with this, and also for getting me obsessed with RvB in the first place.

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He used to ask D stupid questions sometimes, back when he wasn't quite adjusted to the whole sharing-his-brain-with-another-conscious-entity thing. It was easier to make a joke out of the shit that scared him. Easier to make a joke out of Delta.

"Hey D."

A pause. "Do you mean 'Delta', Agent York?"

"Yeah, sure. D. Anyway, I was wondering. If two trains travelling at the same speed collide with each other, and one of those trains is named Charlie, and one of them's overloaded with pizza, then – based on the position of the sun at the time of their collision – which train is winning?"

Another pause, and then, quietly, "I know what you are trying to do, Agent York. I know you do not like me."

'Course, then York felt like an asshole, and he'd have to spend the rest of the day trying to make the little voice in his head feel better. Which, okay, didn't bode too well for his sanity. But come on. You had to take what you could get. You had to appreciate what you had. You had to listen to the little green glowy guy in your head and just be glad you were one step ahead of Wash when they lined you all up for their psycho experiments.

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And it got better. It did. He figured out pretty quick that it was easier to deal with another person living in your head when you actually made the effort to, y'know, talk to the guy – treat him like he was another person. None of the others seemed to have this strategy, but then again, he was the guy with the logic A.I.

They started with the basics.

"Hey D, what's your favorite color?" York had asked idly one day between missions.

"Why would I favor one color?" D had responded after a pause, clearly struggling with the concept.

"I dunno, 'cause you like it," York had said, shrugging. This didn't seem to be a clear enough response for D so he tried again. "And…well, it...it's just more attractive to you than any other color."

"I see," D said, though York could tell he didn't – not quite. "What is your favored color, Agent York?"

"Green, funnily enough. So this works out pretty well."

"Oh. Good."

They'd fallen into a sort of companionable silence after that, or at least an amiable one. After that it got easier, and they had plenty of conversations, long ones, about all sorts of things. And even if it was a little one-sided sometimes, York could never really say he was lonely for somebody to talk to.

That was one thing about the Freelancer program – they made sure you were never alone.

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The insomnia arrived in fits and starts soon after the program started. More often than not he would attempt sleep only to find himself stuck in Super Alert Freelancer Mode, helpless to break out of it.

"Hey D," he said one night, rolling over onto his back, sheets hopelessly tangled at his feet.

"Hello, York," D replied, appearing beside him with a familiar faint green glow – the only light in the room. "It is two o'clock in the morning. You have a mission at nine o'clock in the morning. It is advisable that you sleep now."

"Yeah, I guess," York muttered, stretching and folding his arms under his head.

"Why aren't you sleeping, York?" D asked after a moment.

"Don't feel like it," York said, shrugging.

D paused. "Agent York, your energy is very low. There is a 67.9% chance that you will not survive if you go on this mission without having slept."

"Yeah…" York sighed and raised a hand to cover his face. "I'm tryin', D."

"I do not understand."

"About what?" York asked, lifting his hand slightly to look at D.

"If you are tired then you are supposed to go sleep," D said, sounding mildly perplexed. "I do not understand why this should require further effort."

York couldn't help a quiet laugh. "Oh, that. That's just one of those human-things I told you about. Sometimes our heads or our hearts or whatever get in the way of our bodies. Remember?"

"But your head and your heart are part of –"

"I know, I know, it's sort of a metaphor or something, D. What I mean is – I mean that sometimes we feel mad, or sad, or something, and then it's hard to close your eyes and just sleep, bam, like that. No matter how tired you are."

D was silent for a moment and York could feel him attempting to process this information. "Then are you sad or angry, York?" he said at last.

"I dunno, D," York said after a pause. "I'm trying to figure that out myself."

See, sometimes you didn't want to tell the voice in your head what he already knew, what he could get by processing your thoughts, even if he sometimes didn't get the emotions part right. Sometimes you had to at least pretend you still had a little bit of privacy. You had to pretend that you could still keep something to yourself. Or that you had a self to begin with.

"Do you need help?" D asked.

"No. No, I just wanna –" Figure it out on his own? Impossible. No such thing anymore.

"I understand," D said, before York could come up with an alternative ending to that sentence. "The process of accepting an A.I. implantation takes time and patience. It is understandable that you would still be experiencing difficulties. I can be quiet for a while if you need me to be."

Rattled off like it was from an instruction manual – York was faintly impressed. "Just stay," he said. "Can you do that? Can you stay, keep that glow going?"

It wasn't that York was afraid of the dark. Just, he didn't like it much. When you had one bad eye sometimes it was hard enough trying to make sense of things in the light.

"Certainly," D replied. "May I ask why?"

"It's nice," York said, yawning now and rolling over onto his side. Exhaustion was starting to overtake anxiety at last. "To get a little light in here."

He fell asleep soon after that, Delta beside him, glowing in silence against the darkness.

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If D wasn't fond of being used as a night light, he never said anything about it. Never thought anything about it either as far as York could tell. He just stayed when York asked him to, and that was all.

And that was all York thought he needed, really. Somebody to stay.

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Death wasn't dark, and that was a huge relief. He'd wondered about that sometimes – that was what had kept him up, actually, sometimes. But it wasn't, it wasn't dark and it wasn't light, it was something altogether different, new and strange – and he would go there alone, he realized – for the first time in years, he would be alone.

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He used to ask D stupid questions sometimes, especially toward the end when it all fell apart. ("What's the point of all this shit anyway?" and "What d'you think our chances for survival are if we run?" and "You think there's a chance that Wash is okay?")

And D answered to the best of his abilities, god fuckin' bless the little guy. ("I do not know," and, "At this point in time, we would have a 15.4% chance of survival," and, "It is possible, but unlikely.")

"Hey D," he'd said when they were working the lock on some rundown little store about five minutes before Tex showed up.

"York?"

"D'you think it gets dark when you die?"

"…I do not know."

"Me either. But I sure as hell hope not."

D said nothing, but York could sense his hesitation – a strange prickly feeling somewhere in the back of his mind.

"It's all right," York said, before the A.I. could tell him that it wasn't. "You and me, we've got nothin' to worry about. We'll be fine, okay?"

And for once, Delta did not answer him with a calculation. Instead he hovered at York's shoulder for a moment before responding quietly.

"I hope so, York."