After half a month of training at the G2 base, Vivi naturally brought Karoo to the training grounds. Taking advantage of the chance to spar with Binz, she picked up "Rokushiki: Tekkai" from him, and "Rokushiki: Shigan" from Ain.
Adding those to the "Rokushiki: Soru" she had previously acquired from Smoker, she now had three of the Six Powers under her belt.
Since Binz and Ain hadn't consumed any Devil Fruits, their strengths mainly lay in Rokushiki, swordsmanship, and unarmed combat.
Having already mastered Armament Haki to the point of hardening, Vivi now shifted her focus toward Observation Haki.
Attribute collection was still her fastest route to grasping Haki—no contest.
If she were present during Luffy's fight with Katakuri, she'd probably unlock Observation Haki within minutes. Unfortunately, such opportunities weren't easy to come by.
Though Zefa knew of her interest, he was still recovering. A few moves from him now would be fruitless, and Vivi wasn't heartless enough to set up a surprise attack just to trigger her Haki.
During their initial meeting, Zefa still engaged in light sandbag training and mobility exercises. But after Vivi extended Alabasta's olive branch to him, he stopped training outside of teaching.
Knowing the original storyline, Vivi had a strong guess why.
Zefa was likely preparing to venture into the New World to battle the Four Emperors and notorious pirates. To do so, he needed to restore his full combat power. When he realized his prime—the infamous "Black Arm"—was out of reach, he accepted the World Government's suggestion to replace his right arm with a Kairoseki-powered mechanical one.
But things had changed. If Zefa accepted the offer to move to Alabasta and operate in the first half of the Grand Line, there was no need to regain his former strength. Even notorious names like the Big Helmet Pirates or the Executors weren't on Vivi's radar—let alone Zefa's. As a former admiral, even crippled and aged, Zefa was still the equivalent of a level-80 raid boss. He could handle most pirates with his eyes closed.
Still, Vivi was frustrated. If she couldn't pick up Observation Haki, she'd just have to learn it.
She formally approached Zefa. "I want to learn Kenbunshoku Haki," she said.
"You can't use Observation?" Zefa was genuinely surprised. During training, he'd seen how sharp Vivi's senses were—dodging unseen strikes and reacting to blind spots. That level of perception went far beyond ordinary.
While strength and speed could be gained through constant training, perception was different. Few pirates or marines knew how to improve it—it relied heavily on talent.
Typically, when someone's senses reached a certain threshold, they awakened Observation Haki. Zefa had assumed Vivi was already at that stage.
"I really can't," Vivi admitted. She wasn't sure if her heightened senses from her transmigrated soul counted for anything. Logically, she should have unlocked it already. But she hadn't sensed anything resembling Observation Haki.
She guessed it was due to her already-high perception stats. Other transmigrators could cultivate or practice magic to extend their mental edge, but in the world of One Piece, where physical effort ruled, her edge was capped. The only skill aligned with perception was Observation Haki—and even that wasn't triggering.
Zefa thought for a moment, unsure of the problem. He decided to start with orthodox training.
"Kenbunshoku Haki is the potential within everyone. The key is sharpening the five senses to detect the presence and emotions of living beings. But Observation is harder to train than Armament. Are you prepared?"
"I'm ready."
Using his years of teaching experience, Zefa blindfolded Vivi and sent Ain to spar with her.
Ain fought with dual short swords and emphasized precision, speed, and ruthlessness. She had sparred with Vivi before and admired her technique, but compared to Ain's agility, Vivi lacked strength. Against an opponent of equal skill, that deficit became dangerous.
"Be careful!" Ain warned, stabbing straight at the blindfolded Vivi.
For a swordsman, losing vision changes everything. Ain remembered being blindfolded once and getting pummeled by Binz. She looked at Vivi with a grin of sympathy—this was going to be rough.
But to her shock, Vivi blocked the stab cleanly—perfect form, perfect timing. She even returned a slash that nearly cut Ain's left arm.
"IDIOT! What are you thinking?! Focus!" Zefa bellowed from the side.
Snapping back, Ain repositioned. She dashed left, then cut right in a feint—but Vivi's sweeping strike forced her into a parry.
Both were using Marine swordsmanship. Ain was more practiced, but Vivi wasn't aiming to win. She was focused solely on grasping Observation Haki. Her attacks were calm, steady. Ain grew more impatient.
Their blades clashed again and again. Despite being blindfolded, Vivi parried, dodged, and blocked—even counterattacked.
Over thirty exchanges passed in seconds. Zefa watched, his expression serious—a professor who had just discovered a new thesis topic.
"Stop!" he called out. "I get it now. You're someone with heightened hearing. You're using sound to track your opponent's moves. You've surpassed the average threshold—and that's your problem. You're too high, not too low."
He turned to Vivi. "Block your ears."
Now deafened and blindfolded, Vivi struggled. From defending against three moves to barely parrying five, the sound of clashing blades echoed like a percussion symphony. Ain looked increasingly worn out.
Fighting a blind, deaf person who could still react? Was she the one without talent?
Zefa furrowed his brow in thought. Then a flash of insight struck. "I see… It's scent. You're sensing by smell, aren't you?"
He turned back to Vivi. "Put on a nose clip. Mask your sense of smell too."