Disclaimer: I don't own Naruto or any of its characters.

Warning: Manga spoilers.

Crimson Fog

"Is everyone clear on the plan?" Zabuza glanced around, catching the eyes of each of his companions in turn. There were five of them in all: four of the Mist's Seven Swordsmen, plus Haku. Everyone looked nervous and tense, and with good reason: tonight, they were going to assassinate the Mizukage.

The Seven Swordsmen were the most feared and respected shinobi in the Water Country, and they were typically the Mizukage's bodyguards. But over the past year or so, suspicion had been growing among the elite cadre that something was wrong with their leader. There had been subtle changes in his personality and mannerisms, things that most of the ninja under his command wouldn't notice, but which those whose task was to watch over him at all times had started to pick up on. It was part of a bodyguard's duty, after all, to notice if someone was impersonating his charge, and so they were all trained to look out for exactly the kind of nearly undetectable differences that they had been seeing.

The Mizukage's recent decisions had been erratic as well. For the first year or so after inheriting the position, Yagura had acted the way one would expect a village leader to act: he had sought to strengthen Kirigakure through a judicious combination of diplomacy, trade, and military action. But then, things had changed. Yagura had started implementing decisions that angered the Daimyo and the noble families. He broke off trade agreements, and launched ill-advised raids against other nations. The result of these actions was to isolate Kirigakure from allies both within the Land of Water and beyond its borders. Their country became poorer, and tensions grew.

Anyone could see that the situation was a powder keg, and it was the Land of Water's Daimyo who lit the spark that set it off. He claimed that the Mizukage had sent one of the Swordsmen to assassinate him. While it was perfectly true that Hoshigaki Kisame had tried to kill the Daimyo and absconded with Samehada when his attempt failed, Yagura protested that this had been done without his knowledge or consent. Kisame, he said, had acted on his own. The Daimyo didn't buy it, and urged all the shinobi who were "truly loyal to the Land of Water" to rise up against the Mizukage. And so the Water Country had been plunged into civil war.

The war had raged for years, and caused the deaths of many of Mist's best fighters. The Advanced Bloodline clans were the fiercest warriors on both sides. Because both factions used them, their presence prevented either side from winning a decisive victory, and the war dragged on. Many came to blame the Bloodline clans, and some were wiped out. Zabuza remembered the day he had seen Haku sitting against the railing of a bridge, shivering while the snow fell around him. He had noticed that the snow fell only on that bridge, in a clearly defined cylinder around the boy. The Yuki clan had fought for the Mizukage in the civil war, and Zabuza had battled alongside some members of that family, so he recognized the Bloodline instantly. By that time, the first thoughts of rebellion had already begun to form in the back of his mind. Yagura, once a brilliant leader, had been spectacularly ineffective at ending the civil war. Some of his decisions bordered on outright incompetence, and there were whispers that he was deliberately prolonging the conflict for some reason. In back rooms warded with anti-spying jutsu, Mist ninja had begun to speculate on the possibility that their military leader had fallen under some foreign influence. If the Mizukage had betrayed them and it became necessary to overthrow him, having one of the few remaining Advanced Bloodline users on their side would be a great asset, so Zabuza had taken the boy under his wing.

He was now very glad to have done so. Many of Mist's shinobi, including one of the Swordsmen, were still loyal to Yagura, and Yagura himself could wield the fearsome power of the Sanbi. There was a high probablility that their mission would fail, and Zabuza had no intention of dying here. Haku had set up one of his ice mirrors some distance away from the Mizukage tower as an emergency escape route for himself and Zabuza.

Looking at his co-conspirators, he saw the same look of determination on every face. "Let's go," he said tersely, and strode up to the door of the Mizukage Tower.

The Tower was a stone fortress that had been built in the early days of Kirigakure. People only called it a "tower" because that was how all the other villages referred to their Kages' residences; it was actually a rather squat and blocky structure. The huge double doors that comprised the main entrance were made of thick wood reinforced with doton chakra. Zabuza pounded a fist on the door and waited. He felt a spike of chakra as one of the seals placed on the door identified him: had he been an outsider, even touching the door would have activated the traps that Zabuza knew were hidden around the courtyard. The doors creaked open, and the guard on the other side bowed respectfully. "Enter, Momochi-senpai."

Zabuza marched through, with the rest of the Swordsmen and Haku in tow. "We need to speak to Mizukage-sama. It's urgent."

"I'm afraid Mizukage-sama has left orders not to be disturbed under any cirumstances."

Zabuza glared. "It's a matter of the utmost importance for the security of Kirigakure."

The guard shook his head apologetically. "I'm sorry, Momochi-senpai, but..." While he was speaking, Zabuza pressed his hands together in a seal.

The Mizukage Tower was perpetually dark and cool, with condensation beading on the stones. Now, that condensation began to evaporate, turning into mist that filled the corridor. "Hey-what-" The guard dove for the alarm seal on a nearby wall, but Zabuza cut him down before he could reach it. Looking behind him, he saw Mangetsu withdrawing his hand from the face of the guard's companion. The man dropped to the floor, face blue and eyes bulging.

The group proceeded further into the Tower, incapacitating any guards they encountered. They slipped through Zabuza's mist like ghosts, and most of the guards fell before they even realized what was going on.

On the third floor, they found a figure standing before them, brandishing a torch. He swung it through the air, and its flames wrapped around him like a scarf, burning off some of the mist. Zabuza's eyes narrowed in recognition as this new opponent tossed his torch aside. "Jinin-san."

Jinin's gruff face betrayed his sorrow as he hefted his hammer and sword. "I had hoped it wouldn't come to this, Zabuza-san. Did you think that I wouldn't figure out what the rest of you were planning? Our group has spent too much time together to successfully keep secrets from each other."

"Look at what's going on!" Zabuza exhorted. "Yagura no longer has Mist's best interests at heart. And you can't have missed the warning signs that something is wrong with him."

"All you ever had were vague suspicions," Jinin retorted. "We don't have the right to overthrow a legitimate leader just because we don't like his current policies. We swore an oath to defend him, Zabuza-san."

"We took an oath to defend our country, too," Zabuza growled. He hefted his sword. "Step aside, Jinin-san. You're a fellow member of the Seven Swords, and I don't wanna hurt you."

Jinin shook his head. "No."

Jinpachi had always been one of the most hot-headed members of their group, and now he sprang towards Jinin, swinging the fearsome blast-sword he wielded in an arc over his head. Jinin met it with his axe, and the clanging sound of the weapons clashing against each other echoed through the hallway. With his other hand, Jinin swung his hammer down on his blade. The force of the blow drove Kabutowari through Jinpachi's Shibuki, and the upper part of the massive blade clattered to the ground.

"Heh, do you think that's going to stop me?" Jinpachi taunted. "Even half of my sword is plenty deadly."

"I don't doubt that," Jinin replied. "But your sword also has one weakness." He kicked the torch he had discarded earlier, sending it spiraling through the air towards Jinpachi. Zabuza could see that it wasn't going to actually hit Jinpachi...but it didn't need to. Instead, it collided with his explosive-tag-covered sword.

"Get down!" Zabuza yelled, as the fire set off all the explosive tags at once. He and the others dove to the floor, feeling the whole tower shake from the massive explosion. When Zabuza raised his head, he could see that there wasn't much of Jinpachi left.

But Jinin wasn't in very good shape either. The explosion had set off the tags on the severed half of Jinpachi's sword too, and sent it flying. The razor-sharp half-blade had embedded itself in Jinin's stomach, and he lay slumped against the wall, the light fading from his eyes.

No one spoke for a moment, then Zabuza said, "I don't want Jinpachi-san to have sacrificed his life for nothing. Let's go."

At the end of the corridor where they had encountered Jinin, there was an ornately carved wooden double door. This was the entrance to the Mizukage's private quarters, and as usual, there were two guards stationed outside. They had undoubtedly heard the fight with Jinin, but their orders were not to budge from the door for any reason.

Once again, Zabuza activated his Kirigakure no Jutsu, cutting off their sight. But he added an extra hand seal onto the end of the sequence, and the mist began to coagulate and thicken. It poured into the mouths of the guards, and they fell to the floor, spluttering and clawing at their throats as they drowned.

"Mangetsu-san," Zabuza said, and the youngest member of the Seven Swords dissolved into a puddle of water. He flowed through the thin gap between the bottom of the door and the floor, and they heard the sound of the door being unlatched from the other side.

Entering the room, Zabuza saw the Mizukage sitting in an armchair. He seemed utterly unconcerned by Mangetsu's unconventional entrance, and simply watched Zabuza with mild curiosity. "What brings you here?"

Zabuza knew this nonchalance had to be false, because there was no way Yagura could have failed to notice the battle going on outside. "We believe that you have fallen under an outside influence, and that you are no longer acting in the best interests of the Land of Water. This situation cannot be allowed to continue."

Yagura snorted derisively. "I wasn't aware that you had suddenly been granted the authority to question my decisions. Unless you have proof of what you say, stop wasting my time."

Zabuza briefly glanced at his companions, each of whom nodded in turn. "Then I'm afraid that we, the Swordsmen of the Hidden Mist..." The air around Zabuza seemed to shimmer, and Yagura could have sworn he saw an apparition of a grinning demon above his subordinate. "...have no choice but to take your life!"

Yagura's eyes glowed a vibrant sea-green. "Try, if you think you can." An aura of chakra wavered into existence around him, the same color as his eyes, and the room filled with the scent of the ocean. A tendril of chakra lashed out from the aura surrounding the Mizukage, snaking across the room towards Zabuza. Ameyuri darted forward and sliced through the tendril with her sword. The bolt-sword, Kiba, was the sharpest ever forged-sharp enough to cut chakra. The severed tentacle writhed feebly on the ground for a moment, than dissolved into nothingness.

Another pair of tentacles quickly formed, and they flung themselves towards Ameyuri like deadly whips, but she cut through them as well. Yagura thrust out one hand, and the chakra aura receded into it, warping it into a giant crab claw. Keeping Ameyuri busy with more tendrils of chakra, Yagura tried to slice Zabuza in half with the razor-sharp pincer. Before it could reach him, a blue blur interposed itself between the open prongs of the claw.

"Mangetsu-san!"

The claw snapped shut, but Mangetsu had transformed his body to incompressible water, and the claw found itself unable to close completely. Mangetsu grinned. "You'll have to try harder than that to kill a Hozuki, Mizukage!" He raised a fist and smashed it down on the claw. "Raging Flood Punch!"

There was a sickening crunch as the claw's exoskeleton cracked, and the whole apparatus faded away to leave Yagura with his normal arm. Undaunted, the young Mizukage formed a flurry of hand seals. A sword of water formed in one hand, and a shield of water in the other. The aura of blue-green chakra still surrounded him, and Zabuza knew that he would be using the Sanbi's power to enhance his own speed and strength.

Yagura launched himself at the Swordsmen, only to be met by Kushimaru. Many people were skeptical of the tall, thin ANBU captain when they first met him, because of his ungainly appearance. But as he parried Yagura's every strike, his movements displayed a graceful quality that was unexpected for someone of his height.

Mangetsu circled around to get behind Yagura, and withdrew a scroll from his belt. He unrolled it to reveal seven seals, and placed his hand on one. Immediately, a huge, wedge-shaped sword appeared in his hand. Zabuza immediately recognized it as Hiramekarei, and watched as it began to glow with chakra. Hiramekarei vibrated in Mangetsu's hands as he struggled to control the massive chakra output of the blade. The shroud of energy grew exponentially, forming an extension of the sword. Finally, Mangetsu released the hilt of the weapon, and it slammed down on Yagura of its own accord.

At the same moment, Yagura's form changed. It was similar to what had happened earlier, when one of his hands had morphed into a claw, but the changes were more extensive now. The chakra aura around him contracted and solidified into a full-body exoskeleton, thickest over his back. Three long tails of chakra extended behind him, and the intensity of the energy made the sword and shield he had been carrying boil away.

Hiramekarei struck the hardened plates on Yagura's back. Spiderweb cracks sped across the exoskeleton, but Yagura himself remained unharmed. While the Mizukage was distracted by this attack, Kushimaru lunged forward, directing Nuibari's sharp point right at Yagura's throat. Yagura opened his mouth and spit a jet of pressurized water at Kushimaru. The stream of water knocked him across the room. Zabuza turned to aid him, but saw the gruesome hole the water had punched through his torso, and knew that he was already dead.

A mirror of ice formed in the air above Yagura, and Haku threw a fistful of water needles. The needles found the gaps between plates in Yagura's exoskeleton, and the young Mizukage cried out in pain. As the jinchuuriki reached up to destroy the mirror, Zabuza charged forward and dove to the ground, driving his sword upwards toward Yagura's unprotected belly. Yagura stomped on the side of the blade, and his bijuu-enhanced strength shattered it, but Zabuza recovered quickly and stabbed him with the broken half-blade. Kubikiribocho's ragged edge dug into Yagura's abdomen, and he howled in agony as his blood caused the sword to reform inside his body. Zabuza viciously yanked it free, and heard the crackle of electricity above him as Ameyuri renewed her assault with Kiba.

Yagura screamed again as Ameyuri's razor-sharp swords sliced through his armor, and a wave of chakra radiated out from his body. Ameyuri and Mangetsu were sent flying, and Zabuza felt the inconceivable force pressing him into the floor. From the corner of his eye, he saw one of Yagura's chakra-tails sweeping towards him, and he barely managed to bring his sword up in time to keep it from hitting him directly. Even blocked by the huge weapon, the force of the blow was enough to fling him across the room, and he grunted in pain as he slammed into a wall. Pushing himself to his feet, he saw that the chakra flowing over Yagura's body was closing the terrible wounds Zabuza and Ameyuri had inflicted.

Shit! Even outnumbered, that kid's at an advantage! Time to level the playing field a little. The other Swordsmen and Haku had all trained to fight in Zabuza's mist, so he wasn't worried about impairing his comrades as he formed the hand seals for the jutsu.

As the mist swirled through the room, Zabuza noticed that it was flowing around a suspiciously man-shaped space in one corner of the room, near a rear door. Is there someone else here? Why hasn't he joined the battle?

The door slid open slowly, as if simply blown open by a breeze. It closed just as slowly, and the mist flowed into the area that had previously been vacant. Whoever was here just left. Zabuza quickly assessed the situation. The earlier chakra wave had smashed Ameyuri into a pillar, and she was now slumped unmoving against its base. Yagura was shattering mirrors as fast as Haku could put them up, and even Mangetsu was starting to look worried. They needed all the help they could get, and would suffer if he left the battle. On the other hand, what if the mysterious figure he'd glimpsed was the one manipulating Yagura? If Zabuza could kill him, the control would be broken. They might be able to save Yagura, rather than having to kill him. Zabuza made his decision, and sprinted for the door.

The hallway outside was silent and apparently empty. Zabuza drew in a deep breath, and smelled the scent of another person there. It wasn't a scent he recognized, but he could tell that it belonged to someone old and formidable. The person was standing still, probably waiting for him to come to the conclusion that there was no one there and return to the fight. Zabuza shook his head, trying to give the impression that he was thinking, It must have been my imagination. He turned back towards the door...and then spun around again, swinging Kubikiribocho in a perfect arc as he did so. There was a clanging sound as it hit something hard and stopped dead.

Zabuza heard a chuckle. "I see that making myself invisible will be of no use against you." The air shimmered, and a man stood before him. He was as tall as Zabuza, which was saying something, and he wore an orange mask with a strange black pattern on it. The mask had only one eyehole, and the man carried a steel-edged battle-fan that was pressed against Zabuza's blade.

"Who are you?" Zabuza demanded harshly.

Although Zabuza couldn't see the man's face, his tone of voice gave Zabuza the impression that he was smirking. "And why should I tell you that?"

"Because," Zabuza replied, "I'd like to know the name of the man I'm about to kill."

Zabuza's adversary laughed. "That's a brave remark, coming from a whelp like you!"

"Hardly a whelp," Zabuza scoffed. "You're facing the Demon of Kirigakure, a jounin of the Seven Swordsmen. Now..." Thick mist from the room where the battle was continuing rolled out into the corridor. "Which kill shot should I aim for? Brain...heart...lungs...liver..."

Zabuza felt the pressure against his sword disappear, telling him that his opponent had moved back. His movement is nearly soundless! Then there was a surge of chakra, and the mist roiled around him. The windows along one side of the corridor exploded, and the mist blew out into the night. At the other end of the hallway, the stranger stood with the end of his fan resting on the floor in front of him, as if he'd just swung it downward. He must have used it to generate a fuuton jutsu. Clever.

The other man nudged the bottom of the mask upward just enough to expose his mouth. His chest swelled as he took a breath, which he then expelled as a gout of flame. Zabuza hurriedly formed seals, erecting a Water Prison around himself just as the fire reached him. His keen hearing detected the slight hiss of some of the water being boiled away, but the prison held together sufficiently to keep him from being burned.

He heard running footsteps, and realized his opponent was charging him right behind the fireball. He reinforced the Water Prison, but the other man's battle-fan slammed through it as if it weren't even there. The force of the blow propelled Zabuza through the air, and he felt ribs crack as he collided with the wall.

Despite the pain lancing through his torso, Zabuza pushed himself to his feet. This jutsu is more Haku's specialty, but... The puddle left by the collapsed Water Prison congealed into a cloud of needles that launched themselves at the intruder. To Zabuza's shock, they passed right through him.

Is that some kind of intangibility jutsu? But he hasn't made any handseals!

The man swung his battle-fan over his head, and Zabuza saw that the edge was coated in chakra. That thing's razor-sharp now! He's trying to cut me in half! As he raised Kubikiribocho to parry the strike, a thick panel of ice appeared between him and his foe. Haku's hands reached out of the mirror and pulled Zabuza inside, just as the battle-fan came down. It sliced partway through the mirror, but Zabuza could feel that Haku was already teleporting him somewhere else.

Overwhelming cold assailed Zabuza. He had never been inside Haku's mirrors before, and he wondered how the boy was able to stand it. The frigid air seared his lungs, and his fingers were stiff and numb. He could tell that they were moving through a series of mirrors-each time they jumped from one to another, Zabuza felt like he was going to be sick.

Finally, Zabuza found himself falling facedown onto blessedly warm grass. His broken ribs made any movement agonizing, but he managed to sit up. Running his fingers over his torso, he felt the jagged ends of his ribs under his skin. Hearing a rustling at his side, he turned to look at Haku. The edge of the battle-fan had bitten deeply into Haku's right shoulder, and blood ran freely down the boy's torso. His eyes widened in surprise: few opponents could land even a scratch on the hyoton user. "You're injured."

"I will recover, Zabuza-san. Please do not concern yourself with me."

Zabuza stood in the doorway and watched Haku gazing out over the Hidden Mist. After the stomach-churing chain-teleportation that had gotten them away from the Mizukage Tower, the two of them had limped to the house of one of Kushimaru's former students. The man was an accomplished medic-nin and genjutsu user, and had treated all their wounds expertly. Of course, Yagura had declared Zabuza and Haku missing-nin and sent ANBU to search the village for them. Luckily for them, their host had masked the room in which they were staying with genjutsu, so skillfully that the ANBU who searched his house had no idea it was even there.

Zabuza stepped up behind Haku, and both of them watched the lights of the village glittering through the mist for which it was named. Then Zabuza said, "Haku...Unfortunately, as of today, I am abandoning this country." Rage burned within him as he thought of the mysterious man who had controlled Yagura and forced him to kill the other members of the Seven Swordsmen. It was probably him who ordered the purges that cost Haku his mother's life, too. He may have defeated me today, but I will not let a man like that continue to rule my home! "But one day I shall return, and take control of this land!" Haku looked up at him, and Zabuza just knew he was about to say something silly like, "Don't worry, I'm sure you'll succeed!" So he admonished his protege, "What I need is not consolation or encouragement. What I need is..."

Haku smiled, and Zabuza instantly knew that he had misinterpreted the boy's reaction. "I know," he said. "Please don't worry. I am Zabuza-san's weapon. Please keep me by your side, as your tool."

Beneath the bandages that covered the lower half of his face, Zabuza smiled. "Heh." He's really something else. "Good kid." He turned on his heel and strode down the road, away from Kirigakure. Behind him, he could hear Haku's footsteps following, without even the slightest trace of hesitation. He remembered the ice rising up between him and the Mizukage's puppetmaster, and the bone-chilling cold of the world inside the mirrors. I would have died back there if not for him. "Hey, kid."

"Yes, Zabuza-san?"

"Thanks."

A/N: Ever since Kisame addressed Madara as a "former Mizukage," I'd been wondering whether some of the things that caused Kiri to become known as the Blood Mist Village, like the purges of Advanced Bloodline families and the kill-your-friends graduation exam, were Madara's doing. I also wondered if perhaps the reason Zabuza tried to overthrow the Mizukage was that he got some inkling that he was being manipulated by someone else. The ideas were kicking around in my head, and when the manga showed us the Seven Swordsmen, I started writing this fic.

Ameyuri's appearance doesn't make his/her gender clear, but I made the character female here because "yuri" is more often found in female names than male ones.

Thanks for reading!