Reincarnated in Naruto World with a System

A lost lamb. That's how Uchiha Tatsumi saw himself. And, he had to admit, he had a point. Transmigrating to this world was baffling enough, but then there was the system's constant insistence on him wearing women's clothing. Now, he was about to face yet another violent encounter. Why me? he thought, a sigh escaping his lips.

Despite his trepidation, Tatsumi continued his journey towards the Senju compound. Survival was paramount, after all. He clung to the hope that a display of childlike innocence might soften Tsunade's heart. He was, after all, only six years old.

He walked along the wide street, the Senju clan crest visible on numerous buildings. The Senju compound was surprisingly close to the Uchiha compound. Central Zone wasn't that large, after all. Though, Tatsumi mused, perhaps the proximity was intentional, designed for convenient clandestine meetings between the First Hokage and Madara.

If the Uchiha compound was like a village within the Hidden Leaf, the Senju compound was eerily deserted. It was ironic. The Senju clan, one of the founding families of Konoha, was now a shadow of its former glory. How had the clan that once dominated the Warring States period, even eclipsing the Uchiha clan in its later stages, dwindled to this point? Tatsumi had never asked Nawaki about it, but the question nagged at him.

The Senju clan had seemingly vanished from public view. The only active members Tatsumi knew were Tsunade and Nawaki. He recalled from the history he'd gleaned that after Nawaki's death, the Senju clan would essentially become extinct, save for a few minor characters within the clan itself. What happened?

He considered the fates of other clans descended from the Sage of Six Paths. The Uzumaki clan had been wiped out. The Senju clan was withering. The Uchiha clan was destined for a similar fate in the future. Even the Land of Kaguya clan had fallen. None of the Sage's descendants seemed to have fared well.

Tatsumi arrived at Nawaki's house. It was a large residence, divided into two sections. The back courtyard was off-limits; Tatsumi had never ventured there. Nawaki and Tsunade lived in the front section.

He politely knocked on the door. Silence. He knocked again, a little louder. Still no response.

"Hello?" Tatsumi called out. Could Tsunade be training? he wondered.

He knocked again, even harder this time. Still nothing. Has she gone out? But Nawaki had mentioned that his sister was home and wasn't planning on leaving.

Tatsumi, left with no other option, resorted to his "self-created Ninjutsu – the Wall Escape Technique." With a powerful push from his legs, he propelled himself over the wall and landed silently in the courtyard.

He made his way to Tsunade's house, his familiarity with the layout guiding him. He stopped at the door.

"Knock, knock, knock," he muttered to himself, reminding himself to be polite. "Lady Tsunade, are you there?" he called gently.

Still no answer. However, he could hear faint sounds coming from inside. He noticed a half-hidden window to the left. He strained to peer inside, but at six years old, his height was a definite disadvantage. He couldn't see anything.

Tatsumi, realising he couldn't see through the window, took a few steps back, then jumped, managing to grab the windowsill. With a grunt, he hauled himself up and tumbled into the room.

He found himself in a large, opulent living room. A plush, golden sofa sat facing a low coffee table. On the left wall, a bookcase stretched from floor to ceiling. Tatsumi's eyes scanned the shelves, hoping to find titles related to Wood Style or Senjutsu. But the books were… unexpected. Ten Ways to Discuss the Old Thousand and Ten Benefits of Gambling were just two of the titles that made him blink in surprise.

Suddenly, a faint sound drifted from the back of the house – snoring! Tsunade was still asleep! Tatsumi felt a surge of indignation. He'd waited all this time, even resorting to breaking into her house, and she was still in bed!

He was about to give vent to his frustration when he stepped on something hard and round. Clang! An empty wine bottle skittered across the floor, echoing through the room like a bowling ball hitting the pins.

Tatsumi's eye twitched. Wine bottles? Was Tsunade, at the tender age of sixteen, already a gambler and a drinker? His image of the legendary Sannin shattered before his eyes.

He glanced around. The room was a mess. Empty wine bottles littered the floor, alongside discarded lunch boxes and other debris.

"You smelly little demon, what's all that racket?" Tsunade emerged from her bedroom, rubbing her eyes and still wearing her pyjamas. She looked groggy and dishevelled. "Didn't I tell you to come back tomorrow morning? Why are you here now?" she grumbled.

Tsunade, even at sixteen, had a certain presence. She didn't seem particularly bothered by her state of undress; Tatsumi was, after all, just a child. Though, Tatsumi thought, there wasn't much to see. Even at sixteen, Tsunade was flat.

"It's noon, Lady Tsunade," Tatsumi pointed out, trying to keep the exasperation out of his voice.

"Really? Already? Well, in that case…" Tsunade yawned. "I think I'll just have another nap."

Tatsumi stared at her, speechless.

Eventually, after much cajoling and prodding, Tsunade finally got dressed and they made their way to the Senju clan training ground. Tatsumi plastered a cute smile on his face.

Tsunade, however, was not fooled. She returned his smile with one of her own, though it looked considerably more menacing. "Don't even think about it," she said. "Acting cute won't work on me."

"Lady Tsunade," Tatsumi began, trying to sound brave, "I can explain…"

"Explain what?" Tsunade interrupted. "I don't need explanations. I'm giving you a chance, little demon. My Medical-ninjutsu is top-notch, you know. Even without the Byakugan, I know the human body inside and out."

Tatsumi shivered. Knowledge of the human body…

"And while we don't kill our comrades in Konoha," Tsunade continued, her smile widening, "there's no rule against… thorough training. Let's just say I can stab you thirty times without hitting any vital organs."

Tatsumi swallowed hard.

"Hehe," Tsunade chuckled, her eyes gleaming. "Grit your teeth and take my training. If you can impress me today, I might let you off easy. Otherwise…" Her smile turned positively predatory. "I might just test my limits and have you tell me what thirty stabs feel like."