Kakuzu hates falling into debt.

The thought of it, at least. He'd never experienced the horrors of being in anyone's debt in the first place.

The stitched man of ninety-one years had much blood on his hands. But if there was anything on his list of good deeds, and if there was anything other than his battle skill that he prided himself in, it was that he'd never fallen into debt.

When it came to money, though it hurt, he was willing to spend his own while never borrowing any from a soul. His credit score of life was questionable, but when it came to finances or owing favors, he was completely debt-free. He was a widely feared, self-sufficient, and powerful man in the shinobi world who was setting a great example.

His teammate, Hidan on the other hand…

Kakuzu couldn't recall a day the silver-haired man was not in his debt. He couldn't reminisce on a single moment where he hadn't been the one saving him from the wrath of an underestimated foe, from decapitation, from getting a limb sliced off, along with countless other instances that threatened a headache when thought about. Sure, there had been times that Hidan would take an enemy off of Kakuzu's hands just for fun...and Kakuzu always did the same ten times over.

But something wasn't right.

Something he'd tried to ignore. But then again, it was impossible to since this... thing had come to the point of being a gruesome constant in his life that he could no longer run from. And since continuing to try running was like running away from air—

"C'mon Kakuzu, pick up the pace, would ya? You tryin' to get me killed?!"

It seemed Hidan never grew tired of using that joke. He had a way of dangling his immortality in the air and making it seem as worthless as a dog's chew toy, yet at the same time, as priceless as life itself with every opponent's certain death he lived through. Infuriating.

"Behind you, Hidan!" Kakuzu barked as he jerked and jumped over the shallow sea of bodies that covered the smoky field they occupied. Hidan narrowly dodged the worst of a barrage of kunai shot at his back, some had explosives tags attached to them.

Somersaulting away, Hidan gained a cut ear and ringing eardrum from the small explosion. He caught one kunai with ease, clapping a palm over his ear.

"Son of a... Thanks a lot, Kakuzu! I thought you had my back! You gonna pay for my damn hearing aid, you heathen?" Hidan yelled over the commotion. He caught his footing , slid the metal of the kunai across his tongue, and flung it back at the shinobi who'd thrown it. Embedded in his chest, the enemy went down, and Hidan gawked.

"He…seriously couldn't dodge that? I was gonna sacrifice that heathen. Ah, well... Guess he wasn't as afraid as I thought… Good for him, then."

Kakuzu tried to ignore his partner's commentary. During nearly every battle, when he wasn't busy screaming or cackling his guts up, the Jashinist was mumbling nonsensical, slightly disturbing things to himself that Kakuzu wanted no understanding of.

The ninja regime surrounding the two tightened around them, trying to prevent escape while keeping them a distance apart.

"Kakuzu! You got my back for real this time, right?"

"Don't expect me to babysit you. You'd better stay on your toes." Kakuzu formed hand signs. "FIRE STYLE: DANCE OF A HUNDRED FLAMES!"

A chorus of screams along with the smell of burning flesh. Only five minutes, and they'd taken down three-fourths of this Iwagakure squad of fifty. Only about ten remained. On an average day, Kakuzu would have taken them all on his own and finished them in two minutes at the latest.

"Stay on my toes! Hah! You're one to talk!"

Kakuzu turned to meet the voice behind and was faced with a shuriken that went noticed a second too late, grazing the flesh right under his eye.

The woman who had thrown it was yanked backward away from Kakuzu, receiving a retractable spear from the back through the chest. Hidan pulled it out, hauling the lifeless body over his shoulder.

"You would've usually detected a shitty sneak attack like that miles away! And I'm letting my guard down..."

Hidan swiveled to encounter a bold ninja who tried a frontal attack. The man collapsed to the ground where he met his doom a second later.

Hidan leaned back and fell into another fit of cackles before he cut them off with a growl, looking to the grey sky, a generous spray of blood on his face. "Lord Jashin, forgive your servant! These heathens aren't giving me a chance to take my time offering them to you! But, just give me a little longer!"

Kakuzu took his teammate's distraction with secret gratitude and didn't provide a retaliation to his previous comment. He instead focused on the power in his hits, the smoothness of his dodges, and focused on the names of each jutsu he yelled out, though, on regular occasions, such focus wasn't necessary. He focused on every little detail, anyway. All in order to block out the pain. The searing pain in his lower chest. The pain in his back where the masks that usually held the hearts of powerful ninja he'd encountered were. He needed to block it all out.

He couldn't block it out.

It wasn't the pain along with the returning migraines that came with it that demanded his attention, but the fact that the pain was abnormal that got to him. During the many decades he'd lived in his body, it's no surprise he'd grown very accustomed to it, knowing exactly how it worked. And right now...it just wasn't.

The heat-like flames in his chest, his back, around his hearts— it was spreading. Again. The feeling had been making its appearance for weeks.

In the beginning, the burning sensation would come and go, not to come again for days, and he thought it was nothing more than heartburn. But as time went on, the burn came back more and more frequently until the pain became a permanent resident. Almost unbearable. It wasn't merely heartburn. Unless heartburn could stop a heart completely, that is.

Another particularly sharp jolt of pain shot through him, and this time, Kakuzu couldn't stop his hand from twisting at his chest. He coughed up a thick amount of blood. Fortunately, he'd brought a replacement mask. He thanked the gods that Hidan was still too busy relishing in his fighting to notice. He tore his unsteady hand away from his chest; it now held a motionless heart. It was a good thing he still had two beating hearts attached to his back.

That would make the sixth heart this week. The sixth heart he was forced to replace in the dead of night when all were sleeping except for the unfortunate ninjas he killed for his new lives. He would never tell anyone any of this. No one. None of the Akatsuki knew, and that included Hidan.

That's how it would remain.

…..

"Allll right, so, I was wondering when the hell you were gonna say something."

It was the first noise between the two in nearly an hour. Hidan's voice was drowsy as if just waking from slumber, or as if just waking from death.

Pretending to keep interested in the bingo book he was holding, Kakuzu's gaze hung over the book's edge onto Hidan who was lying motionless on the ground. He was encircled in his sacrificing symbol, his spear still in his chest as he stared up at the roaring sky. The rain fell into his eyes.

Having finished the battle, Hidan chose their last opponent as a suitable sacrifice to Jashin, though Kakuzu didn't recognize her as a potentially worthy bounty. Kakuzu sat on the stairs of an abandoned stone building surrounded by the muddy clearing. Ignoring the water trying to invade his own eyes, he kept his concealed stare on Hidan, who sat up and pulled the weapon in his chest out with a grunt.

"Yeah, I didn't wanna say anything...But apparently, I gotta bring up everything. Pull every single issue outta your stubborn old ass and to the surface. You did good while it lasted, but you should already know you can't hide your pain from me." Hidan cracked his neck, stretching as he stood."I'm able to tell when the devil himself is in pain."

Though the Jashinist wasn't fully looking at him, Kakuzu still made an effort to appear calm. The more disinterested he appeared about this sudden topic of conversation, the better. But…how long had Hidan known? As much as he'd tried to hide his mounting pain, had he really been that obvious?

"You have a lot to say, but none of your gibberish tells me what brings you to actually care," Kakuzu mumbled as he flipped a page of his book. "Not that you need to."

Hidan's eyes narrowed. "Oh, I dunno, maybe I care be-cause knowing you, you'd be twitching on the ground half dead before you told me what the hell's wrong with you. Even when there seriously is something wrong with you, that's why."

"Shut up, Hidan. Since you haven't noticed, I'll point out that I'm far from a child in need of coddling." Kakuzu's mood darkened, if that were possible. It was almost laughable how much Hidan pretended to be concerned about his well being….

In fact, Kakuzu was willing to bet that on an average day, Hidan would have continued to remain 'oblivious' to his problem, silently relishing in his suffering. But today, during their battle, apparently he'd come to sense just how serious Kakuzu's unknown condition had really become. So it was now that he was 'concerned' about what was going on. Please. As if his true intentions weren't to find out just how much this problem would hinder him from having enough time to perform his precious rituals in safety—

Losing his temper like normal wasn't an option. No. Kakuzu would remain calm. Although he'd resolved not to bring up the topic, he could no longer ignore the inner voice shouting at him that he truly had no better choice.

He'd already tried so many things to make this sickness go away, or at least eliminate the symptoms: he'd done more exercise. tried essential herbs. Tried a plant-based diet. He'd taken laxatives and let the gas flow freely. He had increased his water intake. Attempted to reduce his stress levels by engaging in as few conversations with Hidan as possible. He'd even tried reviving his dead hearts through self-administered electric shock via his lightning style. Bad move. That had been an especially bad move. Yeah. Everything failed.

He could see no other way.

"Hidan, I'm..." He paused. Cleared his throat.

No. He wasn't going to say it.

…The last two hearts in his lower back that he'd obtained just two days ago that used to be as strong and healthy as ever, were now as frail as fallen leaves. He could feel their fragile thumps pattering against his back, within the chambers of two masks. They would surely be gone by nightfall. He could not afford to continue this cycle.

His nails dug into the flesh of his knees as he stared down at them. He could only manage to let it out in a low voice.

"I'm dying."

"Huh. Well, duh." Hidan snorted like Kakuzu was out of his mind. "You think you're getting younger every day, old man? You didn't know this, but I've been planning your funeral for about a month now—"

Kakuzu snapped, and Hidan was an inch from his face in a second, a hand gripped deathly tight around Hidan's neck. "Listen to me," he snarled. "My body is no longer functioning the way it has been. You don't need to know the medical details. Just know that at this rate, I really will be dead."

"Arrgh — and what the fuck do you want me to do about it?!" Hidan tore himself from Kakuzu's now loosening grip on him. "Damn you. What? I look like a fucking doctor to you?!" he hissed.

Kakuzu's teeth sank into his tongue, nearly drawing blood. At this rate, perhaps his pride would kill him first.

"...I need your help."

Need. Help. He could barely force the words out, but he made sure to make them perfectly clear; he wouldn't repeat them again. "I want to live."

Going. Going to live. The one thing he'd been telling himself all day long. He had to. And as desperately as he had searched, he really saw no other way than… "And I want to live. Forever."

There was silence for a very long time. A new record of silence for Hidan when it came to replies, who seemed to be in the deepest thought Kakuzu had seen him in, ever. A mix of expressions flickered across his face at an alarming rate. And being one who never excelled in the art of facial expression discernment, Kakuzu could only guess what Hidan was feeling. Maybe that was a look of…shock, followed by confusion…or horror…. disgust...? And Kakuzu was certain Hidan would deny him this...this...whatever it was.

Surely someone like him, one who had openly criticized his religion, the Way of Jashin, the jutsu itself, would never be granted eternal life. At least not in this way. And there was always the possibility it just wouldn't work. Suddenly, it truly was the most ridiculous idea Kakuzu had ever thought of, and fury and self-scorn washed over him—

"What's in it for me?"

Kakuzu had been taking deep interest in the puddles at his feet during the moments of silence. He almost missed those sudden words. He felt like he was waking from a deep sleep as he looked up at Hidan. He blinked a couple times, sure he'd just been hallucinating. But there Hidan was, mouth closed, staring right back.

He was now wearing an unreadable expression. Neutral. Standing still before Kakuzu with hawk-like eyes that strangely seemed to hold no anger. Just scrutiny, perhaps. Kakuzu had never seen him look so serious. There were no signs of scorn, no signs of potential teasing. He'd made his decision.

Kakuzu's fists clenched, but his resurfacing irritation served as his relief in disguise. Hidan would do...whatever he did for stuff like this. But just like a tidal wave, second thoughts washed over him. He disliked Hidan. It was no joke that the man was a seriously unforgivable, insanity-driving pain. Was this really what he wanted? To live a life resembling his? Was his own life worth it? Was it worth what he may become?

His life would no longer be his own.

...No…It would be his own. He would keep it his own. Somehow. His money was worth it - his fortune. The immortality was worth it.

Kakuzu looked back up at Hidan. Pale and dirty skin. Unkempt silver hair now even more plastered to his head from the pouring rain. He held his necklace in one hand, but his purple eyes stayed on him. In those eyes was something Kakuzu never quite noticed before. Light. It was alarming the intensity to which they shone. Unnerving, almost. Eyes like his weren't meant to stay so still. They were meant to roam endlessly in search of action, in search of movement, in search of life worth ending to fuel on his life worth living. They were eyes that testified to the tireless soul behind them… He was forever young….

'... what's in it for me?'

...and he would never die.

"I'll be in your debt."