A/N: Kinkmem de-anon; original request was "Prussia is in a relationship with someone, and that nation ends up dying because of whatever reason. It can be slow or a surprise, the fill can take place before or after the death etc."

Brandenburg was a German Margraviate that intermarried with the Duchy of Prussia. When the male bloodline died out, the rulers of Brandenburg inherited to form Brandenburg-Prussia. Not everyone was happy about this, however, including Poland who claimed Prussia as one of its fiefs and the Holy Roman Empire who tried to stop Brandenburg as well. Eventually they joined together to become the Kingdom of Prussia. Brandenburg now exists as a federal state in Germany, surronding Berlin. And that is the extremely abridged version.

EDIT: Corrected a problem where a deleted second part got posted by accident. That scene has been removed.

Prussia glared down at the toes of his immaculate boots; he'd spent half the morning polishing them until he could almost see his face in them. His uniform was just as neat and precise. Halfway through dressing he found himself digging out a ruler to measure out the spaces between medals and borrowing candles to burn off the stray threads. Their boss would have smiled with pride to see him so smartly dressed; however, he was ruining the effect by sitting hunched up in a chair, his shiny boots digging into the embroidered cushion.

He knew he was being ridiculous, but he couldn't bring himself to care. This is Brandenburg's fault, he thought as he grumbled nonsense. As he let the thought roll around his brain, his ire grew until he could at last force himself to uncurl and straighten himself up.

Across from him in another chair, the cause of his anger was watching him over a pair of reading glasses, gazing serenely at him. Prussia hated it when Brandenburg wore glasses since it just made his resemblance to Austria that much more notable even if he did wear his dark hair unfashionably long. "Are you ready to talk now?" He asked, smile fading behind his stoic mask.

Prussia twitched and glared. "I hate you."

He noticed uneasily that he instantly spotted the tremble of a frown before Brandenburg's thin lips smoothed back out. When had he started to detect the tiny variations in the other's expressions anyway? "And why is that?"

"You know why."

"Humor me."

"Fine. You lied to me, you piece of shit," Prussia growled, pulling his fingers into fists so tightly he heard his knuckles popping.

Brandenburg set his book down and finally took off his glasses. "I never lied. I just thought that the outcome was obvious to you before you agreed to this partnership."

Prussia's hackles rose in a sneer. "Fuck you and your bullshit—you knew I didn't!"

The other German nation sighed, fiddling with his glasses. "Perhaps, but I don't see why you're so upset. You'll be receiving my lands—how much more different is that than conquering another nation and bringing them to live with you?"

"Because I don't want to conquer you, damnit!" he snapped. Brandenburg gazed up at him solemnly, but Prussia could see that he was breathing just a tad too fast. Prussia breathed heavily out of his nose and forced himself not to run a hand through his hair that he spent so long taming that morning. "This wasn't supposed to happen. You aren't supposed to… to go away."

The arrangement—partnership, adoption, whatever you wanted to call, just anything other than calling it flat out marriage—was something that Prussia hadn't seen coming at all. At first their ruling families had intermarried, but he'd thought little of it. But then as the male line of his rulers failed, he found himself in Brandenburg's hands. He hadn't liked the idea at all at first, but anything was better than just fading into a defunct duchy while Brandenburg and Poland squabbled over who had the right to his lands. For awhile, it hadn't been so bad—at least Brandenburg made for a decent companion, one who liked him enough to not constantly tease or taunt him. Their personalities should have clashed, but instead each evened the other out. Prussia could leave the boring politics to Brandenburg and in turn he rode out with the army, where he belonged. When Old Fritz came to him with the idea of truly uniting the two and making him the Kingdom of Prussia, he jumped at the idea. Finally, he had a chance to reclaim former glory and regain his relevancy.

He just hadn't realized that Brandenburg was dooming himself in the process.

"You're going to fade away, you realize," Prussia seethed, tamping down on his repulsed shudders at the very idea. "You aren't going to go out in some blaze of glory—you will age and then wither. You'll be old and I'll watch you die."

"Does that bother you?" Brandenburg asked mildly, as if he was asking him to pass the salt. "Watching me die?"

"Yes!" he finally shouted, at last getting a real reaction out of the other nation when he nearly jumped in his seat. He glared at his now wide eyed companion. "When I agreed to this, you said that we would be equals. Neither one better than the other." He paused, glancing away as he slumped back into his chair. "We were supposed to be brothers."

Brandenburg was silent across from him, neither speaking nor moving. Even his breathing went silent. Prussia gazed back down to his shiny boots and pondered why the idea of being alone once more bothered him so much. It shouldn't—he'd always been alone, even when he was surrounded by humans or other nations. And now, he was definitely going to be alone in the future, even if he would be strong and important again. For some unfathomable reason, it made his stomach knot and his throat tighten.

A slim hand reached into his vision, slowly moving until it took his right hand in its grasp. Prussia let it tug him forward until he slumped forward and rested his other elbow on his knee while Brandenburg gripped his hand between both of his. "I am sorry, Prussia," he said at last. The sincerity in his words nearly choked Prussia; he closed his eyes and tucked his head deeper to his chest. "It was not my intention to… inconvenience you in such a way."

Prussia snorted; leave it to Brandenburg to know the perfect way to phrase that. He would have had to yell and refute it if he said "hurt" or "grieved" him. Instead it was so perfectly tactful that Prussia's pride insisted he go with it.

Brandenburg soothed Prussia's knuckles and Prussia couldn't stop himself from squeezing back. "There is nothing that can be done about it now."

"Yes, there is," he interrupted. "We could-"

"Call the whole thing off and undo nearly a century of work? Of fighting and war and struggling for legitimacy?" Brandenburg butted in. Prussia glanced up to find his (brother/friend/companion/sorta-husband) partner smiling serenely again. "I don't think so." He sighed and sat back, letting Prussia's hand slide out of his grasp.

For a moment, Prussia let his hand hover in the air like that thinking It'll be just like this—one moment he'll be there, the next it'll be just me. He quickly let his hand fall back to his side. "This is bullshit," he said, letting himself sag back into the cushions again.

"I know. Please forgive me."

Prussia considered it before sighing. "Asshole," he grumbled like a concession.

Brandenburg chuckled quietly, less mirth at him and more at the situation. Prussia scowled when he realized he was once again dissecting the other's actions with what he would wager was decent accuracy.

They fell silent for some time, and it was almost normal. Outside the windows, birds chirped, humans labored, and the world kept on turning. But now, each moment was another second lost until Brandenburg vanished. He tried to think of something to say, but for once his rambling inner monologue failed him.

It was Brandenburg who spoke first. "You are right, you know," he began as he pulled out a flask. Prussia raised an eyebrow when Brandenburg took a deep pull before offering it to him. He shrugged and raised the flask in salute before taking a swig himself. When he finished, he admired the container while Brandenburg started to speak again. "I will age and die—eventually." Prussia glanced up at him to see that smile again. "But not anytime soon." That made him sit up and stare. "Your heart will remain the same, but it is my people who will take the seat of power. They will think of themselves as mine still for awhile yet and even then, it is not that I will simply perish. I shall in the end, become another part of you." Brandenburg took the flask back and saluted him with it. "It is not just you becoming the Kingdom of Prussia—it is we who shall." He took another drink. "So you shall not be rid of me so fast as that."

Looking at him, Prussia felt his heart start to hammer. "And how do you know that?"

"Did Rome vanish the instant he went into decline? Did our Grandfather die so swiftly before we all began to grow? No, brother mine, I believe I won't disappear tonight as I sleep." He screwed the cap of the flask back on and tucked it back into his coat before sitting back to meet Prussia's gaze dead on. "Who knows? We might have centuries left."

That should not be so comforting, shouldn't be as welcomed as a soothing hand petting his brow after a nightmare. And yet, Prussia had to fight to not sigh in relief. Instead, he forced a laugh through his mouth, even if it was more of a pitiful imitation. "So, you're saying I might just grow sick of you yet."

The moment the words escaped, he felt his cheeks warm up. Brandenburg, however, kindly ignored the clumsily hidden meaning behind the words and instead reached for his book. "Who's to know?"

For the next few hours, he sat with Brandenburg and talked. Any other day, he would have been driven to distraction at the thought of just sitting there so long without doing anything productive, but not then. The tension had nearly unwound itself from his shoulders by the time the sunset, but when it came time to go to bed, he found himself prodding and doing his best to distract Brandenburg from slumber.

It wasn't until dawn came that he finally let Brandenburg tug at him to lie down. "It's morning and I'm still here. Can we sleep now?"

With one last glance to the sun peeking through the curtains and then to his companion, he settled down and closed his eyes. Just before sleep rose up to claim him, he felt Brandenburg's hand reach out for his.