When October arrived, Jiraiya focused on teaching Naruto how to use Kurama's chakra just like she did. It was clear he needed more help, since whenever he lost focus or lost a bit of control over his chakra, the partial transformation spiralled out of control, turning him into a wild beast. Just like what had happened to Gaara so long ago—or the same thing that happened the first time Naruto attempted this training.
Since she had plenty of free time, considering Jiraiya was focused on her brother, Sasuke and she spent their days training under the watchful eyes of Itachi and Kisame, whom Jiraiya had gradually begun to tolerate. Until something unexpected happened.
"I saw you have a wakizashi," Kisame said, sitting atop a crumbling stone wall. "Do you know how to use it?"
"I could always be better," she replied, eyeing him from head to toe before settling her gaze on the sword on his back.
Kisame jumped down beside her, though he didn't draw his sword. He looked at her with an amused expression and a dangerous smile.
"Maybe later I'll let you play with Samehada. Come on, show me what you've got. You, brat, lend me your ninjatō."
"Hey! Who're you calling a brat, you land-shark!?" Naruto shouted, frowning.
Seina suppressed a laugh, one Jiraiya couldn't hold back. She nodded at her brother so he'd hand over his weapon. Kisame was one of the Seven Ninja Swordsmen of the Mist, so if he was willing to spar with her, she wouldn't turn it down despite him being a criminal. Still, that didn't make her any less nervous about duelling the most skilled kenjutsu user she'd ever faced.
"Let's go."
Seina lunged at him, giving him her full attention. She realized immediately how different it was to fight him. Still, she didn't give up. She spent hours dodging stabs, feinting, ducking, rolling, swinging the wakizashi over Kisame's borrowed ninjatō. She felt sweat beading on her forehead and neck under the scorching sun of the Land of Whirlpools—much farther south than the Land of Fire. Obviously, it wasn't enough.
"Not bad," he said, tossing the ninjatō back to Naruto without even breaking a sweat. "You're better than a lot of people I know."
"I'll beat you someday," she said, lying on the grass. Kisame let out his trademark cackling laugh.
"Maybe. Don't tell me you're already tired?" he teased, looking down at her.
"Screw you."
"Get up, blondie. You'll be my entertainment," he said. "Another match. You and me. No kenjutsu, and no Nine-Tails."
"Fine."
She rose from the grass, much calmer now. She launched at him again, fighting with taijutsu and using earth-style jutsus to gain the upper hand against Kisame's water jutsus. She saw the big grin on the ninja's face when he tried to drown her with what seemed like a massive ocean of water. He really was a monster. Still, Seina grinned slyly. He wouldn't beat her with water. They fought alone for hours. Seina used her powers to make up for Kisame's natural endurance. Soon, he started dodging her spells and curses, noticing how the tree he'd been perched on exploded, instead of just attacking her. She didn't even try to use her chains or her partially transformed form.
Out of the corner of her eye, she saw Sasuke and Itachi watching the fight with their Sharingan active, though they couldn't copy a single spell. She disappeared using her bracelet for the first time—leaving Kisame stunned and catching Itachi's curious gaze. She struck from behind, managing to slam him into the earlier earth barrier. Kisame twisted in mid-air, using the wall to launch himself back toward her even though he couldn't see her. She used the hiraishin to vanish and reappear at a seal she had secretly placed on his clothes. She grabbed his neck, kunai in the other hand. Kisame froze when he felt it.
Kisame's hand touched a leg, moving around her torso, invisible, checking she was really there. He couldn't see her, but he could feel the blade at his throat and her weight on his back.
"How the hell did you do that?" he asked, trying to look over his shoulder even though he couldn't meet her eyes. She reappeared, and Kisame stared at her in astonishment. "What jutsu is that?"
She removed the kunai from his neck, jumping down to the ground. Kisame turned to look at her with a blank expression. Then, slowly, he began to smile, eventually bursting into wild laughter. Seina raised a brow at him. Ninjas really were insane—and that was coming from a witch. He seemed to deliberate silently for a few seconds before finally nodding to himself.
"I've decided. You're going to be my apprentice."
"WHAT!?" shouted Jiraiya. "Hold on! Get your own students, you damn land-shark!"
"Shut up, old pervert," Kisame said without even looking at him. "I've found someone worthy of becoming my successor. Don't you realize what she could do with her invisibility and her powers as the best swordswoman in the Land of Fire?"
Jiraiya grumbled, as he had been ever since he started tolerating Kisame in their group—but everyone knew he did it more out of habit than true hate. It was clear Itachi was completely innocent and didn't mean them harm, and Kisame, despite being a criminal, had no real hostility toward them, except maybe for Jiraiya, who annoyed him from time to time, and he was fiercely loyal to Itachi.
"Shouldn't Seina accept?" Itachi asked from where he sat with Sasuke.
"Fine by me," she shrugged. "I like learning new things."
"Then it's settled," Kisame grinned dangerously. "Hehehe."
"But weren't you already Tsunade's apprentice?" Naruto asked, eating his bento. "And also ero-sennin's?"
"Ha! Suck it, Itachi!" Kisame laughed when he heard that. "My apprentice is the apprentice of two Sannin, a Hokage, and one of the Seven Swordsmen of the Mist."
Itachi rolled his eyes, looking unmistakably like his brother in that moment, literally unable to stop himself. He turned his face away, pretending not to hear him. Kisame, however, seemed to know he was faking it, because he kept smiling in his direction.
"And the daughter of the Fourth," Sasuke rolled his eyes as usual. "Want a medal?"
Jiraiya smacked him on the head when he heard him reveal her identity. Kisame turned to look at her immediately, raising a brow. Seina knew about the grudges between both villages, but she wasn't going to reject his help over something that had happened in the past—before she even existed in this world.
"Now I'm starting to understand more things. Still, that changes nothing."
That's how Kisame almost dragged her away from the others and began to teach her the gruelling training routine the swordsmen of Kiri followed to become the best in the world. She spent hours doing squats, dragging giant boulders, swimming against the strong natural currents of the village, practicing with wooden sticks against Kisame while dodging kunai from his clones, and so on, and so forth. Every morning was more of the same. She stopped practicing taijutsu with Sasuke and Naruto and began training with Kisame, who had a completely different and much more brutal style. One that always ended with several broken bones she had to heal herself.
Kisame, in turn, made her show him all the water jutsu she knew. He was clearly impressed.
"I shouldn't be surprised. After all, your jonin sensei was Kakashi, wasn't he? His reputation precedes him."
Still, Kisame knew a few water jutsu that Kakashi didn't, and eventually taught her. Most of them involved sharks.
"Here," he said one afternoon, after dragging her to the beach. "You're going to need this."
"What is it?" she asked, exhausted as usual but quite curious.
She opened the medium-sized scroll and blinked in surprise. It was a shark summoning scroll.
"All the water jutsu I can teach you depend on three things: 1) that you have large chakra reserves, 2) that you can summon sharks, and 3) that you can breathe underwater. Can you breathe underwater with your powers?"
"Yes."
"Just as I thought. Sign that and I'll show you a few things," Kisame grinned toothily like the madman he was.
Seina agreed to sign the contract. After all, it was never a bad thing to have a second summoning option. She summoned the shark boss and nearly pissed herself when she saw it was bigger than a damn intercontinental airplane. Not to mention the hundreds of massive teeth, each the size of her body.
"I sensed the blood of someone new," said the shark as soon as it appeared. "I never imagined you'd give my contract to another person."
"She's Seina. My apprentice."
"Come closer, girl. Let me feel your chakra."
Seina placed her hand somewhere on its snout, blending her chakra with Kurama's. The moment the summon felt it, it began to laugh deeply, opening one eye to look her in the face.
"You are the jinchuriki of the Nine-Tailed Fox. Working with you will be interesting. Come. Let's take a swim."
Seina breathed through her newly-formed gills and grabbed the shark's dorsal fin. It moved through the water like lightning. She had no idea where they were going, but she could see less and less the deeper they went. Kisame stayed behind while she followed the largest shark in the world into the unexplored depths of the ocean. She didn't want to admit it, but she held a healthy respect for whatever might be down there. She had to use her magic to see in the dark and withstand the water pressure, and she almost regretted it when she suddenly saw a giant squid just a few meters away. Its massive eye stared at them for a moment before vanishing from view, and Seina tried to calm her racing heart.
"Why did Kisame accept you?" the shark asked as it swam, now slower.
"Maybe because no one's treated him like a real person with feelings in a long time. People have always used him. Even when he left the village and joined Akatsuki by his own will, he was still just someone else's puppet. He might be a criminal and maybe he's killed innocent people, but he's also a victim and he deserves more than what his own country gave him."
"… You are very wise for someone so young. Now I better understand Kisame's decision."
"Then, will you accept working with me?" she asked, hearing her words distorted by the water.
"If the most powerful demon in the world has accepted you, who am I to reject the apprentice of a good friend?"
"How do you know Kurama's accepted me?" she asked curiously.
The shark laughed in a low voice. "Can't you feel it in his chakra? Maybe you're just used to it."
"Feel what?"
"He sent me a warning when you blended your chakra with his. He needn't worry; I didn't intend to harm you," she saw the shark's eye glance upward at her, "Though I do find it interesting how possessive he felt. If I had harmed you even slightly, he would've killed me."
"Hn." She figured for a decent jinchuriki, it was expected that Kurama wouldn't let her die. That, and because they were friends.
"Nothing to say?"
"About that, I don't know what you want me to say. About Kisame… I'll take care of him," said Seina, realizing that was the shark's main concern. She patted its back.
After that, Sameten'no—the name of the shark boss—gave her a tour of reefs and other interesting and exotic areas around the Land of Whirlpools. The strong currents were nothing to the shark, who surfed them like they were just little bumps. A while later, he returned to the surface at her request when he sensed through their bond Naruto's nervousness and anger upon realizing she had disappeared. Sasuke just seemed exasperated.
"Hang on."
The shark stood vertically and began swimming with all its strength. Seina smiled as she realized what he was doing. They breached the surface and soared into the air from the momentum. They hit the water again, soaking everyone on the beach, to the shock of everyone except Kisame, who was laughing like a complete lunatic. The shark swam as close to shore as possible without getting stuck. Seina swam the rest of the long way herself, glancing one last time at Sameten'no.
"See you soon."
"Goodbye, Seina. Take care of Kisame."
The shark vanished. She swam to shore where everyone else was waiting.
"Sharks?" Jiraiya asked Kisame.
"If she's going to be my apprentice, she has to learn what I learned."
"I don't think anyone in Konoha has a summoning like that."
"There's a first time for everything."
Kurama jumped out from her seal. He asked her to enlarge it, but Seina had an experiment in mind.
"Try using our link through the adamantine chain and magic to enlarge yourself on your own."
"You think I could?" Kurama blinked. "Maybe you're right."
As soon as Kurama enlarged himself alone, Seina had to hold back a smug smile at having beaten him to it. Kurama rolled his eyes in her direction, listening to her thoughts, but then seemed to vibrate with excitement. He'd been thinking about it for days once he realized that their link wasn't one-directional but bidirectional, as long as she allowed it.
"You know what this means? I can use your magical reserves to do magic myself."
"You'll have to be careful with that. If you drain my reserves, we'll both die."
"I'll keep that in mind. We'll need to train more."
It was late, so they went to dinner. After spending so much time in salt water and having trained all morning, all she wanted was a proper bath. Kurama dozed while she bathed and relaxed, completely clean.
"You're about to fall asleep in there. You'll drown."
Seina yawned. She put on her pyjamas, barely managing not to fall asleep standing, and collapsed into bed. Kurama, now smaller by choice, lay beside her. She felt his nine tails curl around her legs like a thick blanket. The last thing she noticed before falling into a deep sleep was Kurama stretching out, purring on the other side of her back, acting more like a pet than a ruthless demon.
She woke up hours later, blinking as she found her face buried in what seemed to be one of Kurama's paws. She was so comfortable she didn't feel like getting up—even though it was her birthday. Fourteen years old… She couldn't believe it. Kurama stretched. She held back a laugh when she realized he was trying to push her out of bed with his paws.
"As the humans say… Happy birthday."
"Thanks, Kurama."
Kurama watched her grab her things to go shower. When she came out of the bathroom, he had disappeared back inside her.
"Happy birthday, nee-chan!" Naruto smiled when she walked out the door.
"Happy birthday, Naru."
Sasuke, who was already in the kitchen talking with Itachi—curiously, about cooking—turned with a small smile.
"Happy birthday."
"Thanks, Sasuke."
She received a round of birthday wishes from the other men. It felt strangely odd hearing Itachi or Kisame wish her a happy birthday, but she let it slide.
"Don't think you're getting out of training today just because it's your birthday," Kisame said. She groaned in exhaustion. "The road to success is uphill."
"Please stop spouting nonsense this early."
Seina dodged a kitchen knife Kisame threw at her and sat next to Sasuke. She blinked at the plate of food in front of her.
"Who cooked today?"
"I did."
Naruto and she exchanged glances. It was the first time Itachi had cooked. She saw her brother's slightly green face while Sasuke, beside him, started to shake with laughter as he picked up on her thoughts.
"What's going on?" Itachi asked, sitting across from Sasuke at the table, next to Naruto.
"You don't cook like Sasuke, do you?" Naruto asked fearfully.
"Like Sasuke?" Itachi blinked. "He told me he cooks well. He even made you a cake."
Seina suppressed a gag just imagining it. Naruto, pale as snow, set his chopsticks down and clutched his upset stomach. Kisame and Itachi both raised their eyebrows, clearly wondering what the hell was going on.
"Sasuke is the worst cook I've ever met," she replied, smacking the aforementioned on the head for lying. "I only took one bite of something he made and that was enough."
Itachi looked at his brother while Kisame started to grin from ear to ear.
"Is that true?" he asked, though he saw Sasuke silently shaking with laughter. "Hn. I'll have to teach you how to cook something decent, at least."
"Great idea! Why don't you two train in the kitchen?" Seina smiled mischievously.
Sasuke looked at her with betrayed eyes. Wasn't he the one planning to feed them a cake he made himself? She shuddered just thinking about it.
"Is that why you never cook, Sasuke?" Jiraiya asked, walking back into the tent. "I thought it was strange seeing you in the kitchen."
"Damn it, and I had put some of Naruto's candy inside the cake," Sasuke sighed with a small smirk. "I wanted to see what would happen."
"Seriously?"
Naruto burst out laughing at the idea of Itachi or Kisame turning into giant canaries. Seina had to suppress a laugh behind her hand, though it fooled no one, while Jiraiya, Itachi, and Kisame all looked puzzled again. Sasuke waved a hand, brushing it off.
They gave her their gifts right then and there. As expected, it was mostly all ninja gear: new ninja bras, mesh armour, underwear, short-sleeved shirts in black, grey, navy blue, and white, black and white shorts, black capri pants, dark grey summer hoodies, black winter hoodies, etc., etc. It was obvious they had all pooled money to buy her so much high-quality clothing. They had even bought her new footwear, boots and sandals.
"I've got something else for you," Kisame said suddenly. "Here."
He tossed her another scroll. She noticed it contained something thanks to the seal, so she applied some chakra to release it. She blinked a few times, impressed and slightly surprised.
"Isn't this Zabuza's sword?"
"It was. They buried him with it, but in the lore of the swordsmen, it's always said that it's better to pass our weapons on to our successors or apprentices," Kisame explained. "Now Kubikiribōchō is yours."
They went outside so he could explain the sword's secrets. According to Kisame, Kubikiribōchō had special powers like Samehada. Its greatest ability was regeneration. It could be shattered, but as long as she used the hilt to kill someone, the sword would repair itself using the iron from the blood of its victims. Also, it was made of chakra-conductive metal, meaning she could use it with lightning, wind, or any other of her chakra natures. That wasn't possible with her wakizashi or ANBU ninjatō since they were made of inferior material due to the high cost of chakra metal. That's why only seven such swords had been forged in Kiri with that level of craftsmanship.
With this sword, Konoha had acquired two of Kiri's legendary blades—Kubikiribōchō and Kiba, the twin swords she herself had stolen from Raiga and given to her teacher.
"Alright, enough talk. I want to see how you handle your new sword."
They sparred using only kenjutsu. He wielded Samehada and she used Kubikiribōchō. To say it was different from a wakizashi was an understatement. The sword was much larger and therefore heavier, but she easily lightened it with her magic, to Kisame's mild surprise. She also tried channelling her magic through it, but it wasn't as effective as chakra, so she stuck to using lightning jutsus against Kisame—his known weakness. Hours later, Kisame let her rest on the grass while he rewrapped his sword.
"You've adapted well to it, just as I expected. I see it was a good idea to give you that sword. No one else could wield it for that long without your powers, given how heavy it is."
She wasn't surprised. The sword, embedded vertically in the ground, was a full head taller than she was—and Seina was nearly 170 cm tall. She used her magic to weigh it and was shocked to find it came in at 40 kilograms. That was a lot of metal. And still, it was nothing compared to the queen of swords, Samehada. She was beginning to understand why they called Kisame a monster.
That night, she sent a letter to Kakashi, explaining a bit of everything that had happened over the past week. She didn't expect an instant reply since he was likely on a mission, but she knew he was thinking of her and, for now, that was enough.