Boo is a member of the Chinjao family from Kano Country. He is also the vice commander of the Happou Navy there.
Boo is a normal-sized man with long, orange hair. He has tied these in turn into two ponytails. One at the back of his head and the other hanging over the left side of his face. He wears a dark green cloak and light blue-dark blue striped pants, which are held together by a white belt. On his right arm he wears a dark brown glove, an elbow pad and a metal upper arm brace, as well as a dark blue shoulder armor on which is a skull. On his left upper arm he wears a tattoo in the shape of a skull, which is framed by a flame pattern. Additionally, he carries three axes on his back.
Boo seems to place a high value on fairness. So he threw an axe in between when an employee of the coliseum wanted to disqualify Luffy for an early fight with Spartan, although he himself had not started the fight.
Skills and strength
Boo, like Don Chinjao and Sai, is proficient in Kenpo. With this ability, he was able to shatter a fighter’s equipment using a shockwave. According to Sai, no defense could do anything against this ability. Likewise, he is able to use armor haki. However, his abilities do not seem to match those of Sai and Don Chinjao, as he has been defeated more often than his fellow fighters in all combat encounters to date.
Along with Don Chinjao and Sai, he traveled to Dress Rosa to participate in the Fire Fruit Tournament at the Corrida Colosseum. When Luffy was to be eliminated from the tournament early after fighting Spartan in the waiting room, Boo and his brother intervened, the former throwing his axe as the Straw Hat captain did not start the fight himself. When the latter thanked them for it afterwards, Sai got angry and had to be dragged away by Boo.
During the Battle Royals in Block C, Boo did well against the easy fighters. He also had no problems against Kelly Funk at first, when he provoked him and then took him down. After being unable to do anything against his brother, Bobby Funk, with an armor-haki reinforced axe, Kelly asked his brother to “dress” him and then surprisingly defeated Boo with the same ferocity he had previously used to knock out a fighter who was insulting him. With that, Boo was eliminated from the tournament.
None of the three Happo Navy fighters had won this battle, however Luffy gave Don Chinjao his old head form back, for which he was immensely grateful and his resentment forgotten. After thanking him, the three of them headed to the infirmary to have their injuries cured. However, like the other losers of the tournament, they were caught in a trap.
One by one, the fighters were transported out of the room by Trébol and turned into toys by Sugar. Moreover, Boo could no longer remember Chinjao and Sai. When hope was lost, Usopp managed to break Sugar’s curse to the surprise of everyone present, including Usopp himself. Afterwards, Pica unintentionally helped the prisoners escape when he moved the factory with his devil powers.
Doflamingo had already locked the entire island in his birdcage and imposed his diabolical game on the island, causing many of the formerly kidnapped fighters to conspire against the Straw Hats and their allies. However, the Happo Navy did not get involved in the game and instead allied with the Straw Hats along with other fighters. Together, they charged forward to the palace where Doflamingo was currently staying.
As they did so, Pica confronted them in the form of a giant stone golem, as well as soldiers dispatched by Doflamingo. Since Boo couldn’t do anything against Pica, he preferred to fight the soldiers. Ucy managed to jump on Pica’s arm, allowing Luffy, Jeet, and Abdullah to continue on their way and fend off Pica’s attacks. Zoro engaged him in a fight, allowing the rest of the allied fighters to continue on their way to the palace as well. Doflamingo’s soldiers were no problem for the experienced fighters.
However, on the second level, they were awaited by Doflamingo’s commanders. Boo had to fight Machvise, and just like in the tournament, Boo was defeated first by the Happo Navy fighters. He was only able to recover from his injuries with Mansherry’s help. The commanders of the Donquixote Pirates had been defeated by this time and all that was left on the plateau were the common soldiers. The fighters defeated the soldiers and then helped stop the birdcage with the help of Bartolomeo’s barrier. After Luffy’s victory, they watched as the birdcage finally disintegrated. They rested in the royal palace afterwards.
Foundation of the Straw Hat Fleet
While Luffy was recovering from his fight against Doflamingo, the former fighters of the Colosseum discussed how to proceed. They all decided to join the Straw Hat Pirates permanently as allies. After Luffy recovered and the navy – led by Fujitora – moved out to capture him, the pirates fled the navy on Orlumbus’ ship with the help of the civilian population. Once at sea, Cavendish, Bartolomeo, Sai, Hajrudin, Ideo, Leo, and Orlumbus communicated their decision, in the presence of Boo, to Luffy.
The exchange of sake bowls was to seal the alliance. Luffy, however, declined because he felt commanding a fleet of several pirate gangs was too uptight. He didn’t want to have supreme command over them, but rather to continue to allow them their freedom. However, should one of their own ever need assistance, he would rush to help and vice versa should he need their assistance again.
The seven leaders were then only more convinced of their resolve, and declared that if they had freedom to do as they pleased, they would still become his allies, no matter what Luffy might say. Thereupon, the Straw Hat Grand Fleet was formed.
The stories of the self-proclaimed Straw Hat Grand Fleet
Boo, along with the Happou Navy, set off for the homeland. Once there, Sai spoke to his formerly fiancée and broke off the engagement, whereupon she angrily beat him up. His body still completely wrapped in bandages, however, he subsequently married Baby 5, which brought great joy to Boo as well as everyone else present.