Reincarnated in Naruto World with a System

Nawaki felt a sudden chill as Tsunade's piercing gaze bore into him. Although he didn't know his elder sister well, the mere sight of her stern expression was enough to set his nerves on edge. Years of watching Jiraiya's antics had taught him one thing: when Tsunade was in this state, someone was going to have a very bad day. And Nawaki had no intention of being that someone, especially not in front of so many students.

"Um, elder sister, I think my cold is gone... no need to trouble yourself," Nawaki stammered, desperately trying to back away.

"Oh, hold on a second," Tsunade said, her tone deceptively sweet as she grabbed Nawaki's attire, preventing him from leaving. He felt like a trapped chicken in her unyielding grip. If he had looked closer, he would have seen the shadow of terror lurking behind her bright smile.

Uchiha Tatsumi couldn't resist adding to Nawaki's misery. "I saw Nawaki still coughing earlier. With this cold snap in May, we wouldn't want him spreading any flu around Hidden Leaf Village, right? Lady Tsunade, you should rectify this quickly and not go easy on him."

Though he resented the mention of the so-called cold current, Nawaki couldn't help but feel a shiver as Tsunade nodded in agreement. Her smile seemed to freeze the blood in his veins.

"My dear, foolish younger brother," Tsunade began, her voice dripping with mock sympathy. "Even your fellow students can see you're hopelessly sick."

"You, Uchiha Tatsumi, you actually set me up!" Nawaki cried out, his indignation turning to anger as Tsunade's firm grip held him in place. He glared daggers at Tatsumi, who merely smirked in return.

Mikoto, ever the kind-hearted soul, offered her advice. "Nawaki, just confess to Lady Tsunade. She'll forgive you."

Nawaki, realising he couldn't escape, sighed and stopped struggling. Mikoto watched him, puzzled. Why wasn't he kneeling to apologise? Was this the dignity of a true ninja?

Uchiha Tatsumi couldn't help but admire Nawaki's resolve. "Worthy of being the grandson of the First Hokage," he thought.

Nawaki straightened his clothes, a determined glint in his eye. "Admit my mistake? Really?" he said, a rueful smile playing on his lips. "You don't understand, Mikoto. Apology doesn't exist in this context."

Tatsumi frowned, confused by Nawaki's calm demeanor. "Are you planning to escape punishment somehow?"

Nawaki chuckled. "Escape? Tatsumi, you don't get it. If this were a test, you'd score zero. I don't avoid admitting my mistakes out of pride or to escape punishment. The correct answer is—"

Nawaki's words hung in the air, laden with defiance. "Even if I kneel and apologise to my elder sister, she will never spare me."

"That's right," Tsunade said, her grip unyielding. "You need to be cured quickly."

With a swift motion, she slammed Nawaki onto the table, giving him no chance to struggle. "Nawaki, you know my Summoned Beast Katsuyu is good for medical purposes..." Tsunade manipulated a piece of Katsuyu on the table. "Ninjutsu, Katsuyu Interspersed Art."

Before he could react, the slimy Katsuyu was shoved into Nawaki's mouth. He didn't even have time to scream before the bitter, sour taste invaded his senses. His face twisted in disgust, yet there was a faint hint of intoxication in his expression.

"Is this the famous French snail?" Tatsumi thought fleetingly.

"What kind of expression is that? This recipe is specially developed for treating hypocrites and naughty kids, younger brother," Tsunade said with a mischievous smile.

"Elder sister, isn't it meant to treat colds?" Nawaki managed to mumble through the slimy mass.

"Oh, it treats colds too," she said nonchalantly, pushing her golden hair back and revealing a smile that made Nawaki tremble even more.

Uchiha Tatsumi couldn't bear to watch. "It's so miserable... this is so miserable," he muttered, averting his gaze.

Seeing Nawaki half-dead, Tatsumi lamented the seriousness of Konoha's problem children. "Good terrifying woman," he thought, mentally adding Tsunade to his unoffendable list. A person who could treat her own brother so harshly was truly formidable.

Though he had never met Tsunade before, he now understood why her name shook the Ninja World. She was not someone to be trifled with.

At sixteen, Tsunade had golden hair and wore a Jonin outfit. The Yin Seal on her forehead was incomplete, giving her a slightly childish appearance. Her tall, slender figure lacked the mature femininity she would later possess. Tatsumi couldn't help but notice.

"Ah, still flat?" he murmured out, instantly regretting his words.

Tsunade's smile was terrifyingly soft as Tatsumi suddenly found an iron grip on his shoulder. "Let me break all your fingers! One by one, simultaneously!"

Seconds later, Tatsumi found himself with a slimy Katsuyu in his mouth.

Mikoto, standing nearby, sighed. "Really, what's in Tatsumi's head?"

"Uchiha's little demon, come to me next time you need treatment. You're always welcome," Tsunade said gently.

"No, I'm in perfect health," Tatsumi quickly replied, shaking his head vigorously. "What's the joke? Is this really healing? Anyone who receives this treatment should have their brains examined first," he thought.

Realising that one wrong word could be his undoing, Tatsumi vowed to never cross Tsunade again.