Koby

At his debut Koby was a short, plump, jittery youngster, his round glasses framing a face beneath his signature pink hair. Garp's punishing training reshaped him completely, paring him down and stretching him until he stood nearly level with Luffy, while a cross-shaped scar surfaced over his right eye, most likely a souvenir of that brutal schooling.

His hair lengthened into a shaggier cut that kept its pink shade, and he adopted a vividly patterned bandanna across his brow, his glasses now pushed up onto his forehead and lowered mainly for reading. By the time two further years pass, he has grown taller still, reaching Garp's shoulder, and dons a scarf, the coat of a senior officer marked with the word justice, a merit on the jacket, and a fresh bandanna, the forehead scar now wider than before.

In his earliest days Koby was a fearful soul, cowed by both Alvida and her crew, two years of captivity having drained any hope of escape and any wish to become a Marine. Luffy dismissed him as wimpy and useless, yet that same boundless drive lit a matching resolve in him, lending the nerve to defy his captor even with a mace raised over his head.

Sharp and observant, he reads small details and the feelings of those around him, though he was once naive enough to assume every Marine was honorable, a faith shattered by the cruelty shown by Axe-Hand Morgan and that man's son. Rather than crush him, that disillusion hardened his wish to become a real Marine. Once Garp's instruction swapped timidity for confidence, he stayed polite, modest, and easily moved to tears, traits that earned him Zoro's teasing label of crybaby at their Water 7 reunion. Much like Luffy, he acts from compassion rather than bravado, devoting himself to civilians and fellow Marines alike, which made him widely popular.

Born eighteen years ago within the Satsuruzo Kingdom of the East Blue, Koby drifted onto an Alvida vessel during a boyhood fishing trip and was held as a near-slave for his navigational skill, suffering beatings while quietly building an escape boat. Everything turned when he hauled in a barrel that concealed Monkey D. Luffy. After Luffy flattened Alvida with a single punch, Koby found his own voice and was taken on as the pirate's first companion, the two reaching Shells Town together, where they freed Roronoa Zoro and brought down the tyrant Captain Morgan. Koby then parted ways to pursue his goal and enlisted with the Marines.

Beside Helmeppo, he began as a humble chore boy at the 153rd Branch, but their courage during Morgan's escape attempt drew Garp's notice, and the Vice Admiral took both as students. The regimen was savage, and Koby pushed himself harder yet, pounding retired battleships with bare fists night after night despite the bleeding, in time denting their armored hulls as only elite Marines could. He mastered the complete set of Rokushiki techniques, stunning Luffy and Zoro when they met again at Water 7, and during the climactic Summit War his Observation Haki erupted as he sensed combatants dying around him, the shock driving him to stand before Admiral Akainu and beg for the killing to stop. That cry briefly halted the battle, buying Luffy time to flee, and earned Koby praise from Shanks, who shielded him from Akainu's wrath.

His standing soared after the Rocky Port Incident, where he protected civilians and earned the title of Hero, an event that also let Blackbeard seize Hachinosu. Past the timeskip, Koby had risen to Captain and joined the secret SWORD squadron after mastering the Six Powers. He redirected a torpedo aimed at a Levely convoy with his bare hands, then led the Marine push to arrest Boa Hancock on Amazon Lily, standing among the few left unpetrified by her power before the Blackbeard Pirates carried him off. Imprisoned on Hachinosu, he offered himself in place of hundreds of captured soldiers and flatly rejected Blackbeard's scheme to legitimize the island, then broke free with aid from Perona, his SWORD comrades, and an arriving Garp, shattering Avalo Pizarro's mountain-sized island hand with a single Armament-charged blow he called Honesty Impact. The Cross Guild later set his bounty at 500,000,000 berries, far beyond the typical Marine Captain.