Disclaimer: Metal Gear doesn't belong to me.

Author's note: Huh, this is my first text in English. The whole thing was written using a very weird process— which I'll be sure never to use again. I wrote it all in my mother tongue, with the dialogues in English (I can't imagine Kaz and Snake speaking to each other in any language besides English), and then translated the narration. It was long and tiring. But I did it.
This takes place about a month or so after Snake recruits Miller. It highly helps to have listened to the Peace Walker Drama CD, but it's no big deal if you haven't. It's set in late 1972, or early 73, however you wish (South American summer, basically). In my interpretation of how things went from there, Kaz just worked as a mercenary for Snake, although more actively than other recruits, but didn't make his way as second-in-command right away. Also, he probably still felt competitive towards Snake (that part wears down with time though, as we see him more respectful towards Snake in Peace Walker than in the Drama CD). That's where the idea for this small one-shot came from.
And I suck at giving titles to things.

Coffee Cup

The heat of the night had suddenly crawled its way back into the atmosphere of the room. In an abrupt ticking motion of his head, Miller remembered instantly where he was and what he had been doing. He could once again hear the noisy cicadas outside and the mosquitoes hitting themselves against the screen covering the window, which his ears had chosen to ignore to let himself fall into a soft sleep while working. He put his hand to his face in an attempt to rub his eyes, only to meet a pair of sunglasses in the way. He hurriedly took them off, letting them fall onto his desk without a care— he usually was extremely cautious about this accessory of his, but for now, he was too tired to give a damn.

With the tip of his fingers, he brushed aside any leftovers of sleep remaining in the corners of his eyes before moving his hand to slowly rub his temples. When he could function again, he let all of the weight of his head rest on his palm, very softly pulling on the skin of his forehead, as so to keep his eyes open. As some of his hair made its way between his fingers, he could not help but find it a bit too greasy for his taste. He frowned. He had ended up sweating from the summer heat as he fell asleep, and clearly needed a shower. But he had to get this paperwork over with. But he needed a shower...

Another abrupt motion of his head. He was just about to fall back asleep when he clearly didn't have the leisure to. He had promised his boss that he would take care of all the administrative junk this small group of mercenaries could need. And he had to do it. He knew too well how to make his way up in the ranks of any sort of military: rub your superiors the right way with both eloquence and efficient work, and there you had it— bonus points if you got the job done quickly, too. It didn't matter if he had to hide the dark circles and bags under his eyes behind his sunglasses. He had never been so close to achieving his goal.
He just needed to get to a rank from which he could give as many orders as his boss. And there he would have it, his borderless military, his army of mercenaries he had spent so many years envisionning from all possible angles. A dream come true.

As a tentative of motivation, he sighed a tiny smile at the corners of his lips, which he promptly interrupted to yawn and stretch. He lazily rolled his pen between his fingers while his eyes scanned the sheet he had been working on before his sleep, and rapidly got back to duty. Ticking boxes, filling in names, putting down signatures. A long, fastidious and boring process he had gotten used to as the days went by, but that he probably would have given up on if Colombian coffee wasn't as good as it is.

As he almost reached the bottom of the page, he thought he heard the door crack open. He completely ignored it though, blaming the wind for it. But he was soon surprised to meet a hot cup of coffee on top of the papers piled up at his left.

"You might want to consider taking a break," spoke his commander's usual baritone.

No matter how deadly tired Miller was, his typical reflexes never failed to act up on their own. As soon as he met Snake's gaze, he raised his left hand to his face, in an attempt to cover the deep circles of fatigue under his eyes.

"Thanks for the coffee," he mumbled back, incapable of hiding an evident lack of sleep.

Snake wasn't able to restrain a snicker at what he was seeing. On one hand, he was incapable of understanding how one could be so wary of their appearance when they clearly hadn't gotten any proper sleep for many nights in a row, and he found the thought amusing. On the other hand, Miller was in a pitiful state to see, and Snake had even considered putting a sleeping pill in the coffee he prepared, but ended up giving on it, feeling it might not be a very recommandable mixture.

"It's alright if you don't end up drinking it, though," answered Snake a bit late. "It's probably better if you go straight to sleep. You can finish this off later. It's nothing urgent."

The younger man immediately glared at Snake before he could even finish his sentence.

"Thank you for your concern, but,"—he clicked the consonnant of the last word and made a short pause before continuing— "I'm fine."

The one-eyed man stared down at Miller for a while before giving him a little nudge on his left wrist— with absolutely no strength in it at all, but it seemingly was enough for a sleepless person. Not only did his whole arm lose balance on the edge of the desk, but his head also fell down a bit, as he had been keeping it up with the only help of his hand. He quickly caught himself, though, and followed through by glaring annoyedly at Snake.
The look of Miller completely worn by both an intolerable lack of sleep and irritation was actually quite intimidating, he noted.

"I. Am. Fine."

The three words came out very slowly, one after the other, like bullets making their way through a skull.
He reached his arm to grab the cup of coffee his boss had brought him, but didn't get a hold of anything. The beverage was sitting in Snake's hand, who was looking down at him, hiding a tiny smile behind his mustache. If Miller had had a gun of some sort, he might have been exhausted enough to lack both the self-control and rationality needed not to pull the trigger, if that was what it took to wipe the shit-eating grin off his commander's face.
He opened his mouth, getting ready to make a demand—the one of getting the coffee back, adding a "please" to it, because he was willing to use hypocrisy if that was what it took to get promoted. But he didn't get the time to do so, as Snake was already emptying the cup in one gulp, right in front of him. He watched him going at it in awe, surprising himself as he raised his eyebrows—he didn't even know he had enough energy for that much.
In one instant, any and all motivation he had to stay diplomatic completely left his mind.

"What the hell's your problem, exactly?!" he uttered angrily, lifting his pen in the air as if it gave any power to his words, brows furrowed.

His elder apparently looked content with the reaction he drew out of Miller, which was infuriating to watch. But the tired man had no effort left in him to start an argument of any kind, and just ended up staring, waiting for an answer, his lips sealed with anger.
Big Boss softened the look in his only eye and slowly put down the cup on the small plate he had brought with it.

"Now get up and go to bed."

Kaz wanted to answer something—he didn't even know what exactly— but was way too tired to choose his words. He couldn't let his boss worry about his health or sleeping habbits. He needed to be efficient, otherwise he might as well say good-bye to his promotion, good-bye to his life's dream, good-bye to the cicadas outside, good-bye to...
He opened his eyes again. He couldn't let himself fall asleep right in front of Snake. It would give him another argument in his favor. And that was the last thing on earth Miller wanted.
But it still didn't help him in wording an answer.

Snake, on his part, wasn't satisfied that Miller hadn't gotten up. He started again, more aggressively this time:

"That was an order."

Miller frowned. He didn't want to take any orders. His goal was to be the one giving them, and he had heard enough in his life. Besides any of that, the order of going to bed was something he didn't want to obey at all.

"You can't be my second-in-command if you don't get enough rest, Kazuhira."

He was caught completely off guard. It was true that he couldn't be ready to expect many answers when he was tired, but Snake calling him his 'second-in-command' and using his first name, both in a single sentence... was a lot to process.
Being designed as 'second-in-command', even if it were to last only for one sentence, was very pleasing. He had rather been aiming for the title of first-in-command, but had to admit he was content with what he had just gotten. He almost would have smiled spontaneously at the thought— if it hadn't been for his first name. The thought of Snake referring to him as anything other than simply Miller was completely foreign to him. In fact, he had been almost certain his boss couldn't remember his full name.

"... Do you hear me?" asked Snake, with more worry than anger in his voice. He really was wondering if Miller hadn't fallen asleep eyes open on him.

Kaz shook his head with his eyes closed in an attempt to reconnect with reality. He softly opened his lips, staring down at his pen with a blank expression on his face.

"... Yeah," he answered in a low voice. "I'll go."

As soon as he spoke, he closed his pen and neatly arranged some of the sheets on his desk in a way he would be able to quickly manage whenever he would get back to work. He didn't look at Snake once while doing so, though, both because of exhaustion and because he didn't want to show in one way or another that he was pleased by the words his boss had used.
He got up and pushed his chair back, soon closing his eyes to fight a violent dizziness. He couldn't even feel his knees anymore, and his whole body felt numb overall. A warm hand reached for his shoulder, helping him stand up. When he was certain he could walk on his two feet, he brushed away Snake's hand.
He laid his hand on his neck, slowly massaging it while stretching, reached for the sunglasses on his desk, pinned them to his collar, turned his back to Big Boss, and made his way through the door.

"Kazuhira's a long name," flatly declared Snake, forcing Miller to stop his pace in order to concentrate on his words.
The blonde man raised a brow. He wasn't really sure what he was supposed to answer to a remark as random as useless.
"Then just use Miller," he answered thoughtlessly, incapable of making his way into his boss's mind. He turned his head back at Snake, trying to understand.
Big Boss closed the distance between them, his single eye lost in thought.
"Hmm," he let out, softly brushing the hair on his chin. "Besides that?" he quietly asked, looking at Miller.
The younger man wasn't sure what answer he could give. Between this small conversation he couldn't understand and his lack of sleep, focusing on anything was a tremendous effort on his part.
"Well, my friends in college called me 'Kaz', if that's what you're asking?" He couldn't make out what Snake was really interrogating him about. He couldn't even make out that he was having a conversation at the moment, actually. Maybe he had been sleeping and dreaming when he got called 'second-in-command'. Maybe he would wake up in a hospital bed, disfigured by a punch from his superior. Everything was possible.

Snake opened his eye wider and turned it to Miller, as he had the habbit of doing when he noted the man said something relevant.

"That'll do," he answered as he let one of the corners of his lips softly rise in a smile under his beard, "Kaz."

In return, Miller wasn't sure if he was sleeping, awake, dead, or alive. He was about to fall to the ground.
Without any sort of transition, he mumbled a quick "yeah, g'night, boss..." and turned his back to Snake, walking straight down the hallway to his room.
Before he could get too far, Snake stopped him and added:
"First thing you do when you get up is write yourself down as second-in-command officially," he severely said.
That, Miller was able to process easily, without any effort to be made. He didn't turn around, but couldn't help stretching his lips in a wide smile.

"I won't forget," he said, hiding the enthusiasm in his voice by pretending to yawn.