"There are countless pirates with Devil Fruit abilities in the New World," old man Zefa said, pointing at Ain and Binz before turning to Vivi. "Judging by your age, you're no different than these two foolish students of mine. Do you secretly admire the power of Devil Fruits? I couldn't change their thinking when they were young, and now that I'm old, I no longer have the energy to. But I want to tell you something."
He raised his uninjured left hand, and in an instant, a thick layer of Armament Haki enveloped his fist.
Ain and Binz couldn't see the depth of it, but Vivi could grasp part of the technique. She saw that Zefa's Armament Haki wasn't just refined—it was on an entirely different level. His hardening didn't just coat the fist; it looked dozens of times more condensed and forceful than her own.
"What do we, the Navy, rely on to fight against the bizarre powers of Devil Fruits?" Zefa asked. "I've repeated this for forty years, and I'll say it again—Haki. When your Haki reaches its peak, no Devil Fruit can touch you."
Vivi nodded quickly. She understood. Trafalgar Law's Room couldn't move Big Mom because her Haki was overwhelming. If anyone tried using a childish fruit ability against one of the Four Emperors, they'd fail without question.
Haki was an essential ability for the strong. She fully accepted this.
But Zefa's eyes widened in frustration. "Don't nod like an idiot! You don't get it. Don't overthink it, don't get clever. Just now, I saw you trying to make your Haki flow along your fist. For what? It's useless like that! Sturdiness! That's what matters! Understand?"
Roared at again, Vivi shrank back. As Zefa turned to bark at the other two students, she quietly wiped the sweat from her brow.
She recalled that the "Flower Sakura" technique from Wano was a high-level form of flowing Haki. While traveling with the Randoluff Theatre on the way to the New World, she'd pondered it briefly, unintentionally exposing a bit of the concept during her training—and Zefa had pounced on it immediately.
Still, Vivi accepted the criticism. Her training had been too scattered. Zefa's mastery of Haki was undoubtedly top-tier. Learning from him could only help.
After finishing with Ain and Binz, Zefa returned to Vivi. Though he didn't say it outright, his disdain for his two students' slow progress was obvious. It was almost like he felt ashamed as their teacher.
When teaching, however, Zefa was truly professional. He had spent decades guiding students in mastering Haki, the Six Powers, and swordsmanship. No matter the question, he had an answer.
Vivi pushed aside all distractions and focused on learning this academic form of Armament Haki from Zefa.
After an hour of intense instruction, she rushed back to her quarters, eager to practice.
Only after Vivi left did Binz lower his voice. "Teacher, didn't you say…"
He didn't understand why Zefa's attitude had changed so abruptly. The teacher had seemed ready to dismiss her, but something had shifted.
Ain, the female swordsman nearby, wore the same look of confusion.
But Zefa's response left them even more puzzled.
"I saw it the moment the princess walked through the door. She has the air of a ruler—an aura rarely seen in this world. For someone like her to appear now… perhaps a new era is upon us."
There was a strong sense of fate in his words. Neither student understood, and both wisely chose not to press further.
For the next half month, Vivi questioned Zefa endlessly.
Picking up attribute fragments had indeed improved her combat power rapidly. But those memories and instincts belonged to others. They were disjointed and messy. She hadn't formed a personal system. Against true masters, this lack of cohesion could be fatal.
Under Zefa's guidance, she began consolidating her skills. She discarded the axe techniques from Brogy the giant, her old chain skills, flintlock tricks, daggers, and pirate-style hammer tactics. Instead, she focused entirely on the sword—keep a sword in your hand and commit.
At one point she joked, "Isn't a sword inconvenient? Can't kill without it."
Zefa roared, "What nonsense! Who said that?!"
"…Someone called Miyamoto Musashi."
"Stop with the nonsense! Practice the Navy sword style I gave you a hundred times! Master it completely!"
Besides swordsmanship, Zefa also gave her blunt, honest feedback. "Your sword talent is decent. But focus on Haki. With strong enough Haki, no one can touch you."
Thanks to his coaching, Vivi was now able to imbue her blade with basic Armament Haki. This synergy between swordsmanship and Haki drastically improved her overall strength.
The charging time for her special move, Chopping, shortened noticeably.
One particular technique—Lion: Thousand Cut Valley—made Zefa's eyes twitch. As an old adversary of the Golden Lion, he recognized the resemblance immediately. When Vivi claimed she picked it up during battle and could only perform a weaker version called Lion: Nine Cut Valley, Zefa didn't press further. "This sword style's got no secret formula. You just need one thing: practice."
Improving her physique and acquiring a superior blade could come later.
However, when it came to the move Elbaf Spear: Supreme Hegemony, even Zefa was stumped.
Some of his students had included giant lieutenant generals, but none had ever learned that sacred technique. After hearing Vivi describe how it worked, Zefa spent several days analyzing it.
"I doubt you'll ever use that one," he finally said. "Unless you grow to the size of a giant. And the Nefertari family doesn't have giant blood, right?"
Vivi quickly shook her head.
"It takes too much stamina. It's rigid, impractical," Zefa said. "Big Mom has a similar technique—I've seen her use it. She calls it Ikoku Sovereignty. I believe she altered it from the original because she couldn't use the giant's version."
Zefa, while preferring fists to weapons, wasn't ignorant of blade techniques. With his help, Vivi restructured the original Hegemony move. Though it lost some power and had a longer charge time, the modified version—Ikoku: Sovereignty—was born.
After three days of exhausting training, Vivi finally saw it appear on her panel:
"Sword Technique: Sovereignty Lv1."