During these six years filled with laughter and adventure, Shiro never stopped growing. Every morning, he trained rigorously under Rayleigh's strict guidance.
Sweat soaked his clothes, his body was covered in scars, but he never relented. Two and a half years of training left him still relatively weak. Another two and a half years brought some improvement, but the results were hardly impressive.
Finally, after years of relentless effort, in his sixth year with the Roger Pirates, Shiro successfully awakened low-level Armament Haki. That surge of power within him elevated his strength to a new level.
Alongside physical training, Shiro devoted himself to exploring the full potential of the Paw-Paw Fruit. This legendary Devil Fruit, once wielded by Bartholomew Kuma, had never truly been used to its full capacity in the original timeline. Shiro understood that Kuma's simple-minded nature and gentle heart limited its potential.
Thus, in his spare time, Shiro immersed himself in research, pushing the fruit to new heights.
In healing, he discovered that transferring injuries with the Paw-Paw Fruit required a medium to bear the damage. If no suitable medium was found within a certain time, the injuries would return to the original victim.
Where Kuma would absorb the pain himself out of kindness, Shiro found a more practical solution: capturing Sea Kings. Whenever someone was injured, Shiro would transfer the injuries to a Sea King, allowing it to bear the pain. This not only solved the healing problem but also helped supply food for the crew. Of course, the injured Sea Kings were not eaten—they were returned safely to the sea.
Shiro's curiosity didn't stop there. He wondered:
"Can I transfer injuries to inanimate objects, like weapons?"
He reasoned that injuries were fundamentally internal damage. If he could transfer that damage to weapons, the internal structure of the weapon would alter—essentially tempering the weapon.
Excited by the idea, Shiro began testing ordinary weapons, transferring injuries bit by bit. Unsurprisingly, the first attempts shattered the weapons. Yet failure only fueled his determination to explore further.
Shiro also discovered that the Paw-Paw Fruit granted instant movement, hinting at mastery over certain spatial and temporal laws. Late at night, he would stare at the vast starry sky, pondering the fruit's full potential.
According to his calculations, fully mastering the Paw-Paw Fruit might even allow him to teleport into space or travel through time. This bold idea drove him to continue exploring the fruit's secrets.
After countless nights of study and experimentation, Shiro finally discovered a breakthrough. He decided to amplify the Paw-Paw Fruit's spatial properties, creating a never-before-seen technique: Spatial Restraint.
Spatial Restraint allowed Shiro to create a temporary, invisible spatial domain—a cage that could perfectly enclose an opponent. Inside, the enemy's movements were severely restricted. Against opponents of equal or lesser strength, it became a game-changing tool, granting Shiro full control of the battle.
Of course, if his opponent was overwhelmingly powerful, the effect would diminish rapidly.
Previously, the Paw-Paw Fruit's offensive power had been limited to shockwaves and "palm slaps". To improve precision, Shiro sought advice from the crew's legendary sniper, Petermoo.
Petermoo, a master marksman, shared his expertise generously, emphasizing the importance of Observation Haki. For a sniper, Observation Haki was like a sixth sense, allowing anticipation of danger and target movements.
Shiro's instant movement power made him a sniper's dream, enabling him to shift positions and strike unexpectedly. He hoped to teach Shiro his shooting techniques, to combine gunfire with the Paw-Paw Fruit's abilities.
Shiro, however, politely declined. With his shockwave attacks already highly versatile, he saw guns as unnecessary. The shockwave, generated by compressing air into a high-pressure sphere and releasing it from his palms, was not only powerful but also flexible for long-range combat.
He did, however, develop an even stronger technique: the Pressure Cannon. By striking the air with incredible speed, Shiro could pierce through targets, dealing devastating damage. The pressure and destructive power far surpassed that of ordinary shockwaves.
Using a gun, he reasoned, would only limit the fruit's potential.
To awaken his Observation Haki, Shiro began rigorous training with Petermoo's bullets, dodging them to stimulate his potential. For safety, the bullets were not imbued with Armament Haki, while Shiro covered his own body in Armament to withstand the impacts.
Through this painstaking training, Shiro's mastery of the Paw-Paw Fruit, Haki, and battle tactics steadily grew, inching him closer to becoming a truly formidable force in the seas.