One Piece: Sensei System

As Karoo waddled into the dojo, Lucius found himself facing an unusual teaching challenge. He'd taught countless students over the years, but never a giant duck. For a moment, he wondered how he could possibly convey complex martial arts techniques to an animal that couldn't speak.

Then he remembered the horses and dogs he used to train back on the farm. They couldn't talk either, but they'd been some of his best students as they were patient, attentive, and eager to learn. The key had been clear demonstrations and consistent positive reinforcement.

Besides, from what he'd observed of Vivi earlier - her refined manner of speech, diplomatic personality, and the way she carried herself had made him suspect she was some kind of nobility, possibly even a princess - Karoo wasn't an ordinary animal. The duck could clearly understand human speech, even if he couldn't respond beyond quacks.

"Alright, Karoo," Lucius said, maintaining the same serious tone he used with his human students. "Vivi tells me you're already skilled at running. That's good - Tempest Kick builds on leg strength and precise movement."

"QUACK!" Karoo stood at attention, his posture impressively disciplined.

[Student Analysis - Karoo: High physical aptitude, excellent focus. Recommend practical approach]

More training dummies materialized around the dojo. Lucius demonstrated the basic kicking motion again, creating a small wave of compressed air. "The key is to compress the air along your leg's path. Think of it like... cutting through water when you swim."

To his surprise, Karoo immediately attempted to mimic the motion. His first try produced only a slight breeze, but his form was remarkably good.

"Excellent!" Lucius praised. "You're already grasping the basic movement. Now, let's work on power generation."

Over the next hour, Karoo proved to be an exceptionally dedicated student. While Luffy had needed constant redirection and Usopp had required confidence building, the duck maintained perfect focus throughout every exercise.

[Student Progress - Karoo: Exceptional coordination and learning speed]

By the second hour, Karoo was consistently generating visible air pressure with his kicks. His natural leg strength, developed from running through desert sands, gave him a significant advantage.

Vivi had returned to watch the training, but she didn't seem surprised by Karoo's rapid progress. "The Spot-Billed Duck species of Alabasta are known for their intelligence and physical capabilities," she explained. "They've been bred for generations to serve as elite messenger birds and royal guards."

Lucius watched as Karoo executed another perfect practice kick, this time creating a small but distinct cutting wave that sliced halfway through a training dummy. The duck's progress was remarkable - far beyond what he'd expected from his three-star potential rating.

'Why did the system rate Luffy as five stars but Karoo as only three?' Lucius wondered. 'Based on what I'm seeing, it should be the opposite...'

A commotion from outside interrupted his thoughts. Through the dojo windows, they could see Nami yelling at Luffy and Usopp on the beach. Apparently, Usopp had pushed Luffy into the water as a joke, forgetting about the Devil Fruit user's inability to swim. They'd managed to pull him out quickly, but now he was lying on the sand with his belly comically inflated like a balloon.

"MEAT!" Luffy's voice carried clearly to the dojo. "Nearly drowning makes me hungry! I need meat!"

Lucius sighed, reminded of how his teenage students would always be starving after physical education classes. "There might be some rabbits in the forest," he said. "I could go hunting-"

"QUACK!" Karoo interrupted enthusiastically, spreading his wings.

"I think Karoo wants to help," Vivi translated with a smile. "He's an excellent hunter."

"Would you like to join us?" Lucius asked Vivi. "Since you and Karoo are partners, it would be good to practice coordinating your techniques."

"I'd love to!" Vivi's eyes lit up. "It would be interesting to see how Shave could complement my existing fighting style."

As they headed into the forest, Luffy's voice followed them: "Hey, no fair! Why does the duck get to go hunting?"

"Because Karoo can already do Tempest Kick," Usopp pointed out sulkily. "A stupid duck is better than the great Captain Usopp... impossible!"

"Better than the future King of the Pirates too," Luffy pouted. "I need to train harder!"

About a hundred meters into the forest, Lucius turned to Vivi. "You mentioned having combat experience. What's your fighting style?"

"I use these," Vivi pulled out what looked like jewelry - a pair of small rings attached to wires. "They're called Peacock Slashers. By spinning them quickly, I can use them as weapons."

"Would you mind demonstrating?"

Vivi nodded, then began spinning one of the rings. The wire extended, the ring becoming a deadly blur as she controlled its path with subtle movements of her pinky finger. She sliced through several small branches with precision before retracting the weapon.

"Impressive," Lucius said genuinely. "The control required for that must be incredible. I can see how Shave would complement it perfectly - you could create openings with your speed, then strike while your opponent is disoriented."

"QUACK!" Karoo suddenly tensed, his head turning sharply to the left.

"He's spotted something," Vivi whispered.

They crept forward quietly until they saw a group of rabbits in a small clearing. Before Lucius could suggest a plan, Karoo burst into action. The duck executed a perfect Tempest Kick, sending a blade of compressed air that cut through a low-hanging branch. As the branch fell, it startled the rabbits directly toward Vivi, who deftly caught two with her Peacock Slashers.

"Excellent teamwork!" Lucius praised, genuinely impressed. He'd meant this hunting trip as a break from training, but they'd turned it into an impromptu combat exercise.

They spent the next hour moving through the forest, with Karoo flushing out prey and Vivi making the captures. Their coordination was flawless, speaking to years of partnership. Lucius found himself largely unnecessary, except for offering the occasional suggestion about incorporating their new techniques.

"Try using the Shave footwork between strikes," he advised Vivi after one particularly athletic catch. "Even if you can't perform the full technique yet, the practice will help build the necessary muscle memory."

The light-hearted atmosphere made it easy to forget they were technically in the middle of martial arts training. Vivi shared stories about growing up with Karoo, while the duck acted out particularly memorable moments, making them all laugh.

By the time they headed back, they'd caught an impressive number of rabbits. Lucius thought it would be more than enough for everyone, but Vivi shook her head.

"You haven't seen Luffy eat yet," she warned. "He can consume more food than you'd think possible."

Lucius looked skeptical. "That skinny kid? How much could he possibly..." He trailed off, remembering how nothing in this world seemed to follow normal rules. "Though he has been talking about meat an awful lot."

As they approached the beach, they could hear Luffy's excited shouts: "I smell meat! They're back with meat!"

"QUACK!" Karoo puffed up proudly, clearly pleased with his hunting performance.

Looking at the duck's satisfied expression, Lucius felt that familiar teacher's pride. Sometimes the best students were the ones you least expected - even if they happened to be giant ducks who could now slice through the air itself.

He just hoped they'd caught enough rabbits to satisfy a rubber man's appetite.