Disclaimer: I don't own Naruto.

"And Yōton makes five."

Kakuzu dropped the corpse of the Iwa-nin as the tendrils of Jiongu brought the man's heart into his own body. That task taken care of, he massaged the back of his neck with one hand, tilting his head one way and then the other until he heard a satisfying crack. He stared at the motionless body of his latest victim, green and red eyes blank.

It had taken over 110 years, but the old bounty hunter was bored.

He wasn't even sure how it had happened, but the combination of circumstances over the years had resulted in a world that left little for him to do. In order to challenge himself, he'd set about collecting the various specialty chakra natures of shinobi the world over, his mastery of the primary five elements completed long ago. With the addition of the (technically second) Lava Release heart, his collection – Boil, Explosion, Magnet, and Storm, as he wasn't allowed to touch Suna's Scorch-users – was complete.

The burning question of what he was to do next remained unanswered, and Kakuzu wondered if he'd finally approached the end of his time.

He'd seen and done much in his life, more than most shinobi could claim they'd ever be able to accomplish in several lifetimes: joining Akatsuki's inner circle, savoring the destruction of Konohagakure – the only village aside from the Hidden Waterfall to be a source of his loathing – raising a Jinchūriki to become the Kage of a new world power…

Not to mention that the world was in the nearest state of peace it had seen since before the Warring Clans Era.

Of course, he could always stir the pot – start a war and reap the benefits as he'd done thrice before during world conflicts – but the old nukenin found that he didn't want to. While tentative peace wasn't something he had ever sought – hadn't even considered as a possibility, to be honest – he had to admit that the idea of a unified world didn't repulse him as much as he'd expected it to…probably because his former pupil was essentially its overseer.

Naruto… Somehow, everything started and ended with his protégé. If Kakuzu hadn't found the blond at the impressionable age of five – hadn't tried to kill him and in turn be impressed by his regenerative abilities – how different would the world – would he – be? Akatsuki's plan might still have succeeded, but there was no guarantee that the bounty hunter would've played the role he did in it. He'd wasted a lot of time watching over Naruto and running errands for Akatsuki, time that would've otherwise been spent bounty hunting for pleasure…the same thing he'd done for decades. But thanks to that chance encounter with Naruto, his life had gone from monotonous to adventurous.

Kakuzu had never quite figured out if that had been a good thing or not, but as he refused to live with regret, he'd merely returned to his old ways and tried to balance his newer experiences with the older ones.

His amusement at causing Naruto suffering, for instance, had to be checked. While it would be fun to make trouble for the blond by stirring the pot, he was also indebted to his young disciple. Naruto had proven six years ago that he had the power to beat his ex-teacher, passing the test Kakuzu had planned for him since they'd met almost 30 years ago. If there was one thing the bounty hunter hated, it was owing someone something, and so he had tempered his inclinations to cause the Amekage anguish and instead focused on more (destructively) constructive pastimes.

He brought his hand up to eye level, staring at the ring still placed on his middle finger. One of the reasons he'd remained loyal to Akatsuki even after the organization's breakup was that following the will of Pein was the only gesture he could think of to repay the man for his actions – saving his life after dying at the hands of Konoha-nin (Kakuzu refused to give Naruto credit for that) and letting his disciples live.

It was about the only thing he could do to honor the man's efforts and sacrifice.

The rustling of trees drew him from his memories, and he looked up in time to see two blurs pass by, a platinum blond being chased by a figure with Naruto's nostalgic shock of yellow hair. Curiosity piqued, he took off after the pair, tracking them silently. The pursuer's arms moved in a way that Kakuzu assumed he was forming seals before he threw them forward with a called, "Raiton: Mahi-mō!"

Interesting, thought the bounty hunter, watching as a net of lightning chakra flew towards the platinum blond. The other shinobi – one wearing the white flak jacket of a Kumo-nin – turned around, absorbed the attack, and then fired it back at his pursuer with increased power. Stupid as Naruto, to use a Raiton attack against a Kumo-nin, Kakuzu considered snidely, but quicker on his feet, he rectified, observing as the blond exhaled a gale of wind chakra to cancel out the attack.

A retrieval mission, perhaps, he thought, interest piqued further as he analyzed the non-lethal Lightning Release attack the young shinobi had used. A blond wearing the shinobi outfit of Amegakure…that was almost too much of a coincidence for him to ignore. Knowing that the mystery would bother him until he could solve it, the former Taki-nin sighed to himself. Just as with that brat so long ago, a little assistance from one more experienced is necessary.

Moving a bit faster so that he was nearer to the Cloud shinobi, he formed two quick hand signs, his focus on the ninja ahead of him. Jiton: Kinzoku Hikikomi, he thought, reaching out for the metal comprising the Kumo-nin's weapons and buttons.

In the next instant, the Cloud shinobi was flying towards a tree of Kakuzu's choosing, where the magnetic force of his Metal Pull technique kept him immobilized. The blond seemed to take the unusual behavior in stride – just like Naruto would, Kakuzu thought with snide amusement – descending upon the hapless shinobi and dispatching him with a slice of wind chakra applied to a kunai. Brutal…efficient…

Three kunai were thrown at his position, forcing him to dodge or be skewered by more wind chakra. "Who's there?" called the blond.

More intelligent than he looks, too. Kakuzu stepped out from his hiding spot, arms hanging loosely at his sides. The blond's blue eyes widened just slightly. "You…you're…Kakuzu…" he breathed in awe.

Now that Kakuzu had a good look at him, the resemblance was unmistakable. "And you are the brat's little pawn."

The boy frowned at how dismissive the taller shinobi sounded. "His knight, actually," he muttered, somewhere between offended and embarrassed. "My name's Keizo—"

"I am aware of who you are," Kakuzu interjected in a tone that indicated he could care less.

Keizo seemed to be caught flatfooted at the older shinobi's apathy, and he lapsed into silence for a moment before trying, "…Dad says you're like my grandfather."

Kakuzu cringed internally, though he refused to let any sliver of emotion pass over his visible features. Apparently Naruto's years as a family man had imparted upon him an even stronger sense of sentimentality than he'd possessed during his teenage period, and he was passing it down to his children. He considered refuting the claim, not wanting to get sucked into his blond pupil's warped views of family, but then he paused.

When he'd been a boy growing up in the Hidden Waterfall Village, hadn't the one thing he'd sought above all else been his grandfather's approval? Granted, it had ultimately left him with nothing but spite and scorn, but the fact remained that most children looked up to their older relatives. And while Kakuzu had intentionally remained taciturn and withdrawn in his dealings with Naruto in order to mold him into the ideal shinobi – into his second coming – he held no such expectations that Keizo would follow the same path, regardless of how he treated the boy.

Plus, if he was anything like Naruto, Keizo would just run with whatever small irritations Kakuzu let on, so, instead of retorting with his normal snark, he let the term of endearment go and instead asked, "What has your father told you about me?"

Keizo looked thoughtful. "He liked to tell us bedtime stories about you, but I don't think we ever really believed them until you came to Ame and fought him. You're…scary strong."

Kakuzu allowed himself an amused smirk beneath his mask. Practically a mythological tale to children, like the stories of Susano'o, Tsukiyomi, and Amaterasu…how my infamy has been embellished. "I see…" Green eyes glanced over at the corpse of the Kumo-nin. "Tell me about him."

"Spy," the blond sighed. He scratched the back of his head in a gesture reminiscent of his father when he was at a loss. "It looks like Kumo and Iwa are working together to launch one more offensive against Ame and its allies."

Kakuzu scowled to himself. Years ago, when Naruto had given him the task of dealing with the Raikage, he'd only been able to delay the man's plans. Unlike the Mizukage, the Raikage's shinobi prowess had proven an adept counter to Kakuzu's strengths, and in order to fight another day, he and his partner had been forced to flee prematurely, despite how sour a taste it had left in his mouth.

Over the following years, there had been rumors of the Hidden Rock and Hidden Cloud colluding together, especially as the threat of the bomb that had destroyed the Hidden Leaf had faded into obscurity. Even with his pride wounded in his fight with the Raikage, Kakuzu had refused to get involved further, considering the problem his pupil's, not his. Now it seemed as if the rumors were coming to a head. A final battle, then, he mused. "Tell me, pawn—" Keizo opened his mouth to protest the nickname, but Kakuzu continued before he could, "—how prepared are you to participate in this coming war?"

"I dunno…I mean, it's us, Suna, Oto and Kiri, so I think we're good—"

Kakuzu was already shaking his head; the boy had misunderstood his question. "Fight me."

"Huh?"

"Fight me," Kakuzu repeated, his tone brooking no argument.

Keizo's expression morphed into one somewhere between stunned and terrified. "Are you gonna kill me?"

The bounty hunter resisted the urge to roll his eyes at the naivety of youth. Instead, he reached into his cloak and pulled out a book from the pocket he normally kept it in. "Are you in here?" he questioned, making sure the boy could see the words that labeled it a Bingo Book.

"No…?" Keizo replied slowly, clearly unsure whether that was the correct answer to give.

"Then your body is worthless to me," Kakuzu told him, choosing not to say 'you are worthless to me' as he would have with Naruto. He put the book away, musing idly on his previously-unfounded magnanimity. "No, I wish to test your mettle. You may attack with whatever tricks you possess."

Naruto's son looked unsure, but as Kakuzu stood stolidly and simply waited for the boy to take some sort of action, he seemed to realize the old nukenin wasn't joking around. Slowly, almost in expectation of the former Taki-nin to stop him, he began to form seals. "Raiton: Rakurai," he announced, tongues of bluish-white lightning chakra crackling about his fingers.

He pointed at Kakuzu, and a bolt of the energy lanced forward in an attempt to skewer the taller shinobi. The bounty hunter frowned beneath his mask as he sidestepped the attack, dodging the next several bolts the blond threw at him. He telegraphs his attacks too loudly. The lightning stopped suddenly, and Keizo withdrew two kunai from his pouch and came charging at Kakuzu, thrumming blades of wind chakra erupting along the lengths of the knives. There is a predictability to his assault that exposes him to retaliation, he observed, remembering the lesson he'd taught to and (re-)learned from Naruto – predictability killed; dodging the slashes of the elongated weapons was practically second nature to a man of his caliber.

"Why…don't…you…fight…back?" Keizo huffed, accentuating each word with another slash of his weapons.

And he possesses Naruto's shortsightedness. The apple does not fall far from the tree. "I was unaware that I should do so. Are you testing my mettle?"

"No, but what's the point of hitting a target who won't hit back?" he snapped.

"You have yet to hit me," Kakuzu intoned matter-of-factly, "but if you insist…" He waited for the right moment in the boy's movements before planting his fist squarely in Keizo's stomach. Despite not having his Earth Spear technique active, Kakuzu's punch still sent the blond skidding back a number of feet and forcing him to his knees, breath coming in choked wheezes. "The first lesson you should take from this is to not ask for more than you are prepared to handle," he lectured, advancing upon his adversary. Reaching him, he grabbed the boy by both shoulders, lifted him into the air, and twisted casually, heaving him into the nearby treetops. "Secondly, do not retain a rhythm to your attacks…it leaves your opponent the opportunity to discover and exploit it." When there was no response from the surrounding forest, Kakuzu announced, "You may continue when you are sufficiently recovered…this exercise is not yet over."

Silence greeted this proclamation, forcing him to assume that the blond had taken his words to heart and was actually planning his next move. It was an interesting experience to once again be passing down the tricks of the trade to the younger generation, albeit in a more direct capacity than he'd used with the boy's father.

Not that Naruto hadn't proven himself a capable shinobi under his tutelage, but Kakuzu had always known that he wasn't the most adept teacher.

But this situation was different. Kakuzu had no reason to manipulate this child, no reason to discourage what lessons he could impart in the short window of time he'd been presented. Keizo also had no preconceived notions of what Kakuzu was like – barring whatever fairytales Naruto had cooked up as bedtime stories for his children – and so the bounty hunter saw no purpose in disguising his intentions with sarcastic barbs and deadpan putdowns.

A whistling of wind caught the nukenin's attention, and his focus shifted to a small sphere of condensed chakra that was barreling towards him. Green eyes narrowed in careful analysis of the assault. So, Naruto taught him Fūton: Kussaku Kūkidan. Impressive. He took two steps backward before the Drilling Air Bullet impacted the ground just in front of him, creating a massive gale of hurricane winds that kicked up dirt and forced Kakuzu to shield his face from the debris. The boy learns quickly, he noted, to stop announcing his attacks and create a smokescreen. However…

He turned and brought his arm up, knocking aside the chakra-laced kunai Keizo had been prepared to stab him with. "How…?"

"You are not the first to attempt such a strategy," Kakuzu stated, "though I give you credit for your increased stealth."

Keizo released a sound that Kakuzu almost called a growl before jabbing at him with one hand. The former Taki-nin took another step back, causing the attack to come up short, and then continued to evade as the blond moved into a fast-paced series of strikes. Kakuzu observed the pattern as he continued to dodge and block, mentally tallying the few openings that presented themselves. This taijutsu style is familiar…

After another minute of allowing Keizo to fruitlessly attack him, Kakuzu stuck out his arm at the next jab, black threads erupting from the long suture around his forearm and winding around the offending limb. The bounty hunter reveled in the way Keizo's blue eyes widened in surprise, silently approving how the boy was taken off-guard for only a moment before using his other arm to try and free himself. In response, more threads wriggled their way out from under his skin, creating a makeshift set of manacles that kept the blond suspended in midair, immobile. "Is this Jiongu?"

"Yes." Kakuzu peered at him curiously. "Naruto did not impart upon you this secret?"

Keizo shook his head. "Dad doesn't use it when we spar…said it's dangerous. He told me that once I become a Jōnin, he would let me decide whether or not I want to learn the secrets of Jiongu, but…I haven't really seen it used, 'cept when you fought Dad."

Kakuzu slowly set the boy down and commanded the black tendrils to release their captive. Keizo watched the kinjutsu with silent interest. "Tell me, little pawn, who has been in charge of your training?"

"Dad and Harō-san."

The bounty hunter nodded in confirmation of his suspicions. Keizo's taijutsu katas were very fluid, and that and his Raiton jutsu had Harō's fingerprints all over them; his ability to use the Drilling Air Bullet was further evidence that Naruto had also had an understandably heavy hand in his son's growth. "And do you desire to acquire Jiongu?"

"Yeah!"

"…Nine times."

"Huh?"

"Nine times I had an opening to kill you in our last exchange," the nukenin elaborated, making allowances for the boy to follow his non sequiturs. "Should you possess the ambition to become another carrier of Jiongu, you will need to become strong enough that these weaknesses are no longer so apparent." He didn't bother pointing out that only a ninja of his own caliber actually had the capacity to spot and capitalize on such openings; what the boy didn't know would only help spur him on to bigger and better things.

"Oh…thanks."

Kakuzu inclined his head once in a gesture of acknowledgment before lapsing into silent contemplation.

The boy was well on his way to becoming an adept shinobi, a future possessor of a powerful kinjutsu capable of maintaining some degree of order in the world. Naruto was smart to not expose his son to the lure that the Earth Grudge Fear technique would have until he was strong enough to wield and understand it properly. That was, after all, the criteria Kakuzu himself had used for his blond pupil – to contain the most powerful of the Bijū and survive the bounty hunter's criticism and antagonism, Naruto had proven himself worthy of possessing the kinjutsu.

It certainly hadn't hurt that the Jinchūriki's background had mirrored his own so well, but that was an excuse that those prone to attachment offered, and Kakuzu considered himself beyond such useless sentimentality.

Still, the boy before him simply seemed to want to improve himself, and the old nukenin could respect such initiative. After all, the motivation for his training a lifetime ago had been to impress the hard-to-please Takahashi Hiroki.

And Hiroki had done nothing but screw his grandson over time and time again.

Kakuzu didn't want to be like his grandfather – didn't really want to be considered a grandfather by the teenager standing before him, if he was honest, though it was probably too late for that – and he certainly didn't want all of his effort going to waste. If you are prepared, there will not be any sorrow. It was a phrase he had picked up not long after his escape from Takigakure, one he'd thought had applied rather well to his life. But such a mindset had made him an eternal pragmatist, and so he'd stopped hoping for things that he saw as beyond his reach.

Perhaps it was time to correct that. "Iwagakure and Kumogakure, you said," he reaffirmed. The boy nodded once, blue eyes puzzled. "Very well." Then, with no other preamble, he began to tread in the direction of the Hidden Rock Village.

"Wait! Where're you going?"

"To remove the opposition."

"By yourself? You'll be killed!"

Kakuzu turned around so that he was once again facing the blond. He unbuttoned his Akatsuki cloak with methodical slowness, holding it in his hand once he'd finished. Then, grunting with effort, the masks containing the hearts captured by Jiongu burst from his back in pulsating masses of black threads, reforming into demonic impressions of animals. One at a time, Keizo watched in awe as the masks unleashed a variety of attacks – flowing torrents of lava, beams of bluish-white light, black whips that caused explosions with everything they cracked against – at the surrounding foliage. "I am a one-man army," Kakuzu informed the stunned boy tonelessly.

"Wow…"

Kakuzu nodded to himself; the display had been enough to convince his 'grandson', and that was enough. The legacy of Akatsuki was that each of the members possessed the abilities and history to strike fear into the hearts of most mortal men, and Pein's position as leader of the organization had meant that he was the most feared of all.

It had therefore come as a surprise to discover that Pein's machinations were to ultimately create world peace, but then again, manipulation was key to surviving in the shinobi world. In that vein, Kakuzu could appreciate the extents Akatsuki's leader had gone to in order to make sure his plan succeeded, even as one who had been used to accomplish its end.

Akatsuki had been composed of broken, deranged individuals all looking for something different – Deidara had craved destruction, Sasori had sought appreciation, Kakuzu had thirsted for money – all working towards an ironic conclusion of Pein's construction.

But with his death, the reins keeping the individual members lashed to Akatsuki's endgame had broken, and everyone had been free to pursue their own goals once again. Some of them were nobler than others; Kisame, for instance, had fought for control of Kirigakure and was currently restructuring its government to reflect his own dream – a world without lies, he'd confided in Kakuzu as they'd prepared to take down Mei and her army. Konan was still in charge of a flourishing Otogakure, upholding Pein's idea of peace by turning the Hidden Sound into an up-and-coming world power. In the spirit of former alliances, the blue-haired woman had offered asylum to any Akatsuki member willing to abide by Oto's (and Pein's) rules, and Kakuzu knew for a fact that both Zetsu and Sasori had their own havens within the Hidden Sound where they dabbled in their respective interests.

But for shinobi like Deidara, Hidan…him…world peace was a detriment. Their reputations were based on carnage and destruction, and with serenity came a lack of cities to blow up, people to sacrifice to a deity who demanded violence…conflict to create powerful bounties for Kakuzu to hunt and fight and cash in for money. But just as the new world threatened their lifestyles, so were they threats to it. That was why he had dismembered Hidan and left him for the buzzards in the middle of the Land of Wind, and why Sasori had a blond puppet with access to the Hidden Rock's prized Explosion Release kekkei genkai.

That was why Kakuzu had embarked on various challenges, including his own Bloodline Limit hunt, to keep his mind off the fact that he was becoming obsolete in a world no longer dominated by the wars that had plagued his life since birth.

Unsure how to mesh into the changing world, Kakuzu had taken a long step back and looked for some other purpose in life. The startling conclusion he'd reached was one similar to Kisame's ideal…not necessarily a world of truth, but one in which shinobi were respected by their villages for risking their necks in the line of duty, for sacrificing everything for the village regardless of whether their objective was achieved.

A world where the injustice of what Takigakure had done to him almost a century ago was nonexistent.

Naruto, Konan, and Kisame had already shown their dedication towards maintaining that type of existence; even the Kazekage had kept a firm hold over the now-recovered Hidden Sand, enough so that the only threats to peace were the Hidden Cloud and Hidden Rock.

And even though Kakuzu harbored a sliver of good will towards building a better world, he knew that he had no place in it. He was too corrupt, too jaded by a century of hardship and exile to survive in the world his fellow nukenin and star pupil sought to build and uphold. Nor did he wish to proactively work towards implementing such change in the same way as his former associates were doing.

In that sense, there was only one move left for him to make, the sheer magnitude of which would earn him his rightful place in the annals of history. For even as Naruto held the world in the palm of his hand, Kakuzu would remain unremembered for his deeds, a puppeteer faded into the woodwork of his greatest masterpiece.

And after how long he'd lived and all he'd accomplished, the former Taki-nin refused to go out like that.

So he would once again leave behind a legacy, but this time it would surpass even what he'd intended for Naruto to become. Kakuzu almost blamed his ex-pupil for how his life had turned out; if he'd never met Naruto, it was entirely possible he'd never become as damnably soft as he now saw himself. Working with, towards, and for the benefit of others…how ingratiating. There was something almost ironic about what he was planning, though Kakuzu feared that if he looked too deeply, he'd find a reason to change his mind, and fickleness wasn't a trait he found very becoming. "You cannot tell anyone that you met up with me," he warned Keizo as his thread-creatures buried themselves in his back. He threw on his cloak and then turned around, withdrawing his Bingo Book once more, along with a pen.

"Oh…" Keizo almost sounded disappointed at the command. "How come?"

There was a brief flash of deep green before Kakuzu turned back around and walked up to the boy. "Here," he offered, ignoring the question and holding out his hand to Keizo, "a memento to remember my lessons."

It was more than his grandfather had ever (willingly) given him, he mused.

Keizo reached out a tentative hand and picked up the ring the older shinobi was presenting to him. It possessed a dark green gemstone with the character hoku inscribed on it, and though the blond knew jewelry wasn't really a thing most men wore, he could instinctively feel that this gesture was important. "It is to be worn on your left middle finger," Kakuzu instructed.

The boy did as the older shinobi bade, letting out a soft "Whoa…" of amazement as the ring – which was rather large for his hand – tightened comfortably around his flesh.

Kakuzu dug into his pocket and came out holding a second ring, this one having an orange gemstone with the character san on it. "For your sister, to be worn on her left index finger," he told Keizo, turning around and flicking the ring at the boy from over his shoulder. As the blond fumbled the catch, Kakuzu gruffly advised, "Tread cautiously, little knight."

Unsure what to make of the warning – and the fact that the older shinobi had given him the appropriate nickname – Keizo merely focused on the ring in his hand. "Yeah…she'll really like this. Thanks, Kakuzu-ojii— huh?"

Kakuzu was gone, the rings and forest's destruction the only things to mark that he'd been there at all.

-l-l-l-

"How'd the mission go?"

"…Fine…"

Naruto arched an eyebrow at his son's distracted response. "Everything okay?"

Keizo fiddled nervously with the ring Kakuzu had given him, trying to sidle towards the door in the process. "Yep. Can I—?"

"Ah-ah-ah," Naruto tutted, holding out his hand. "Let's see what you've got there." His son visibly hesitated before taking the ring off and placing it in his father's hand. The older blond stared at the object for a long moment before quietly asking, "Where'd you get this?"

"…Found it."

"Keizo," Naruto warned.

"I…can't say."

The Kyūbi Jinchūriki hummed in thought, tapping his finger against the piece of jewelry. There was a momentary flash of dark green light, and Naruto kicked his desk over to protect his son from the unknown threat, summoning a shield of Jiongu's threads as he did so for his own safety.

Konan had once told him that Akatsuki's rings contained huge stores of chakra that enabled Pein to use his Magic Lantern Body Technique, among other tricks. Naruto didn't know them all, but for his son to suddenly come across one – especially the one owned by his former mentor – couldn't be a coincidence.

When it became apparent that the ring wasn't going to do anything else, Naruto lowered his shield to find a small scrap of paper on the floor. He picked it up, and after reading the short message, handed the ring back to his son. "Dad?"

"It's yours. Head on home, I'll see you later."

Confused, Keizo decided not to look a gift horse in the mouth and left. Naruto straightened his desk once the door was closed and dropped the paper on it, sighing at the message. 'Bishop to E1', it read.

Naruto looked up at the ceiling, a sad smile gracing his lips as a tumult of emotions raced across his mind. Kakuzu…give 'em hell. You won't be forgotten…I'll make sure of it.

-l-l-l-

Author's Note: Alright, that's it, the official end to everything related to The Cost of Living. Just as the epilogue focused on Naruto's life and accomplishments, this was meant to honor Kakuzu, making him a very grey anti-hero along the same lines of Pein. If you didn't know, just as 'kaku' and 'hi' represent the bishop and rook of shogi, 'kei' is the knight. Also, E1 is the chessboard position of the white king, represented by the Tsuchikage in this case (more importantly, making Kakuzu the black bishop). Let me know what you think of this final epilogue.