Undoubtedly, improving Armament Haki and Observation Haki would certainly be more helpful for one's personal combat power.
It's just a pity that Kenji isn't 16 now, he's 66. If it were 50 years ago, when he had just graduated from Marine School and was entering real combat, he would definitely have leaned towards upgrade choices that enhanced his personal combat power.
Now, he already possesses personal combat power, so he naturally prefers to maintain his physical condition for a longer period, upgrading his Physique.
People's mindsets change with time and age.
Fifty years ago, Kenji was a passionate and aspiring young man.
But now, he just wants to clock in and slack off. If he had to pursue something, it would be to maintain his 'immortal daily routine' of slacking off for as long as possible.
"Life, ah... it's truly interesting."
With a 'slacking off' enlightenment, Kenji began upgrading his Physique trait.
In his vision, the 'deep purple' of the Physique trait changed level by level.
Dark Purple — Super Purple —
Suddenly, a flash of light appeared, and the purple of the Physique trait in his vision disappeared, replaced by a golden hue.
This was Kenji's first gold trait in his life, Physique!
Although it was currently only 'light gold,' just one more upgrade would bring it to normal gold.
However, at this point, Kenji stopped, retaining that last upgrade opportunity.
"Last time, when Physique upgraded from 'Super Blue' to 'Dark Purple,' it evolved Sea Beast Power." Kenji summarized his experience and made a guess.
"If a major advancement of a trait can lead to some kind of evolution, then upgrading Physique to 'light gold' should be enough..."
Kenji silently waited to verify his conjecture.
A moment later, lines of system prompts appeared in his vision.
[New derivative evolutions have appeared.]
[Your Physique trait has reached light gold!]
[Physique (Light Gold) triggers derivative evolution... New trait generated! Superspeed Regeneration!]
[Superspeed Regeneration: Super strong Physique brings super fast self-healing ability, repairing hidden physical ailments, eliminating senescent cells, and maintaining one's physical energy (affected by the rarity of the trait).]
A surge of vibrant energy suddenly arose within Kenji, a long-lost feeling. He had this feeling every day when he was 16.
"Superspeed Regeneration... has my metabolism also sped up?" Kenji unconsciously clenched his fists, tensing them.
"That's right, self-healing is essentially a matter of cell division, so speeding up metabolism is a given."
"I never thought I could be young again at this age."
Flowers bloom again, but youth never returns.
People age, and to a certain extent, they die.
But at 66, Kenji felt the vigorous energy of youth.
"There are many non-human species in this world, and among them, the Giant Race lives more than three times longer than ordinary humans."
Kenji guessed, "Perhaps further upgrading and evolving Physique could raise my lifespan limit?"
However, with so little information currently available, everything was still an unknown.
At the very least, he needed to first figure out why the Giant Race lived so much longer than ordinary humans.
"I'll find an opportunity later... to ask." Kenji refocused his attention.
In his vision, there was still one remaining opportunity to freely choose to upgrade a trait, which he had saved.
After all, system rewards that allowed self-selected upgrades were relatively rare. Most other rewards were random upgrades, completely uncontrollable.
Unfortunately, there was only one upgrade opportunity left, making it impossible to upgrade Armament Haki or Observation Haki traits to gold.
And Kenji also learned from the system prompts that the self-selected upgrade opportunity could not be retained for too long and needed to be used quickly.
"This last upgrade still has to be used on a purple trait."
Upgrading a low-strength trait once wouldn't significantly improve combat power, it would still be weak.
Of course, if a high-rarity trait didn't undergo a major advancement, it also wouldn't have much impact on combat power.
However, Kenji considered another aspect, "What if a future system reward only gives one self-selected upgrade reward? Combined with this upgrade, it would be enough to advance a 'deep purple' trait to 'light gold'!"
With this in mind, he used his last self-selected upgrade opportunity on the Armament Haki trait.
Armament Haki upgraded from 'Deep Purple' to 'Super Purple'. It was just one upgrade away from advancing to 'Light Gold'.
"This time, even if the next reward is only one self-selected upgrade, it'll be enough to advance the trait!" Kenji took precautions, highly satisfied with his prudence.
"Now, it's about time to deal with the trouble at hand."
His Observation Haki had detected an extremely powerful aura rapidly approaching from a distance since a moment ago.
He recognized this aura, it was Kaido.
"That kid, he still came." Kenji shook his head slightly.
He hadn't really wanted to fight Kaido. Each time Kaido had been captured in the past, he had successfully escaped without exception.
The World Government and the Marine seemed to have no way to deal with this monster. The Marine prisons that made countless pirates tremble in fear had practically become his free cafeteria.
Kenji didn't expect any surprises with this capture.
"However, this kid is quite brave, no wonder he'll become the world-renowned 'One-on-One King' later."
Counting Zephyr, there were two Admirals on Kenji's side, yet the other party showed no fear, even charging straight over, as if afraid he wouldn't be discovered.
"Huh? Who's that reckless over there? Kaido?" Zephyr also noticed the commotion, turned his head, and immediately showed an interested expression.
"The strongest Supernova with a bounty of 1.07 billion Berries, right? Heh, I'd like to give it a try."
Zephyr cracked his knuckles, making a 'ka-ka' sound, clearly itching for a fight.
Kenji certainly had no objection. If the location weren't unsuitable, he would even want to bring a chair over and sit to watch.
Just as he crossed his arms, preparing to watch the battle, a system prompt suddenly appeared.
[You discovered that the Supernova riot on Sabaody Archipelago has not ended, and you are determined to continue challenging Supernovas to further enhance your reputation!]
[Mission (Side): Challenge 'Supernova' pirates and successfully survive until the end of the Sabaody Archipelago riot event!]
[Reward: Randomly upgrade an owned trait once!]
"This again." Kenji was somewhat speechless. "When did I decide to continue challenging Supernovas?"
At the same time, the sound of whistling wind came from afar.
Swoosh ~ Bang!
A few seconds later, a figure arrived like lightning, landing heavily on the ground, creating a deep crack.
"Hiccup~ Two opponents, who's first? Or come at me together!" Kaido was very arrogant, his face still showing signs of drunkenness.
"Hmph! Arrogant brat!" Zephyr frowned and punched with anger.
Boom!!
Before the punch even landed, the gale caused by the pressure was already raging, making it impossible to open one's eyes.
On the other side, although Kaido looked bleary-eyed from drinks, his moves were decisive. He raised his spiked club and, reinforced by Armament Haki, struck out with lightning speed.
Bang! Rip~!
Their heavy punch and spiked club collided fiercely, and large, lightning-shaped traces of Armament Haki scattered and splattered.
The tremendous crash of the fist and club caused the enormous Yarukiman Mangrove in the distance to shake, and the nearby ground continued to vibrate violently.
After one clash, both were involuntarily forced backward by the immense impact.