Goddess of Ice; Reborn as Naruto's twin sister

Inside a vast hall deep inside the Uzumaki compound, two pairs of fists met, resulting in a powerful shockwave that caused the two clashing people to slide backward.

"Hehe, not bad, Naruto. It seems like you haven't been slacking off."

Naruto could only smile wryly when he heard Yuna's words.

"Well, I would rather not be thrown into hell due to you finding out that I was slacking, nee-san."

"Yup, that is definitely what would have happened if you did."

Naruto shivered a little and nodded his head while lowering his stance.

"Anyway, should we stop playing around a get a little serious?"

"Of course, let's get started."

Ice started covering Yuna's body while an armor of wind surrounded Naruto. Both of them vanished from where they stood, and yet again, their fists met, but this time, Yuna's ice was trying to freeze Naruto's wind armor, while Naruto's wind tried to shred away Yuna's ice.

The duo separated again, but this time they didn't stop fighting. Naruto's hand slashed downwards, causing wind blades to fly at Yuna, which she swiftly dodged while counterattacking by shooting a few icicles at Naruto, which he smashed apart with his fists.

Next, Naruto took out a three-pronged, orange kunai and tossed it at Yuna, which she swiftly countered by taking out a snowflake-looking one, which she threw towards Naruto's.

Just when the two kunai were about to clash in midair, Yuna and Naruto vanished from their position and reappeared in the place of the previously thrown kunai.

*Clang*

Yuna and Naruto clashed with kunai in hand.

"Now that I think about it, how about we have some fun with this, nee-san?"

"Sure, I'm in."

Ten clones of Yuna and Naruto popped into existence and started tossing six kunai each, and moments later, hell broke loose.

The clones and the originals teleported away to the freshly thrown kunai. They started clashing with each other, resulting in an incredibly chaotic, three-dimensional fight where Yuna and Naruto were constantly teleporting from kunai to kunai with a total of twenty clones doing the same while tossing even more teleportation kunai around.

Meanwhile, Hinata, Anko, Karin, Ino, and Haku were spectating the fight through a reinforced glass window and were slightly bewildered by the spectacle they were witnessing.

"Well, now they are just showing off."

Hinata chuckled when she heard Anko's words and nodded in agreement. Although the way the duo was fighting looked incredibly impressive, there was honestly not much of a point in it. Considering how much chakra it costs to create ten clones and have them constantly teleport around, only people like Yuna and Naruto would dare to use such a wasteful technique. Naturally, that didn't mean that it wasn't an extremely deadly technique.

A few minutes later, Yuna's last clone popped, and Yuna and Naruto landed on opposite sites of the training ground with satisfied expressions on their faces.

"Well, that was fun. we should do this more often, Naruto."

"Indeed. Anyway, let's turn up the heat."

Red chakra that was yellow at a few places burst out of Naruto and created a four-tailed chakra cloak under his wind armor.

"Very well, let's kick it up a notch."

Just like Naruto, Yuna created a four-tailed chakra cloak around her, but unlike Naruto's, her's was primarily blue with some white and red streaks woven into it.

*BOOM*

A loud explosion echoed through the room when Yuna's fist smashed into Naruto's forearm and another when Naruto's free fist, that shot towards Yuna's stomach, was blocked by Yuna's free hand.

Naruto's tails started lashing out at Yuna, but she efficiently managed to block that with her own tails, and moments later, the duo separated again. While Naruto got on all fours with his tails pointing at the spot in front of his mouth, Yuna stood straight with her right palm pointed at Naruto and her tails pointed in front of it.

Massive amounts of chakra were compressed in front of Yuna and Naruto and formed a dangerous-looking, black chakra orb.

""[Bijuudama]""

They shot the chakra ball simultaneously, and the moment they met in midair, both of them exploded, obliterating the ground where the two jutsu clashed while producing a small mushroom cloud.

When the dust settled, Yuna and Naruto were revealed, and both of them seemed to be rather unbothered by the massive attack they just produced. Neither of them were wounded nor seemed particularly exhausted.

"Well, Naruto, how about we crank the dial up to 100. I noticed your clone gathering Natural Energy for a while now, and I'm rather curious to see the fabled sage mode with my own eyes."

A wry smile appeared on Naruto's face when he heard Yuna's words.

"Nee-san, you could have at least pretended that you didn't notice."

"Oh? I guess you wanted to surprise me, huh? Sorry about that, do you want me to act surprised after you pop it?"

Naruto couldn't help but roll his eyes when he heard Yuna's words.

"I don't mind a little pity from you, but let's not overdo it, please. If you act all surprised after you already admitted to knowing about it, that would be a little too pitiful."

"Haha, true, I guess. Anyway, show me what you got, Naruto!"

Moments later, Naruto's clone popped, and Naruto could feel Natural Energy flush his body. He immediately controlled it and mixed it with his chakra, producing senjutsu chakra. Simultaneously, his chakra cloak changed color and became yellow, with black markings mixed in all over it while changing form to look like a full-length haori. Additionally, Naruto pupils turned into a black cross.

"What do you think, nee-san. I call this Kurama Mode."

However, Yuna didn't answer him immediately and instead mustered Naruto's new form. Only after she was satisfied did she nod in approval.

"How interesting; I wasn't expecting Natural Energy to have such an interesting effect. Good job learning Sage Mode, Naruto."

'Well, Hisoka told me about this, but she herself wasn't entirely sure how stuff worked.'

Naruto was rather happy about Yuna's praise, but he felt like something was off moments later. His gaze met Yuna's, which caused Yuna to smile at him. Naruto immediately took a step back while cold sweat started flowing down his back like a river.

'I messed up.'

"Nee-san, how ab..."

"Hehehe..."

Eery laughed escaped Yuna's mouth, causing shivers to go down his spine.

"Ah~ You are radiating quite a bit of power there, Naruto. This should be quite fun~ Yes, quite a bit of fun~"

"N-Nee-san, ca..."

Before Naruto could say anything else, incomprehensible amounts of battle intent flooded the training ground, while a face-splitting grin appeared on Yuna's face.

"LET'S HAVE SOME FUN, NARUTO!!!"

"Ah, shit....I f*ed up"