Sai
Sai is the 13th generation leader of the Happo Navy from Kano Country and a martial artist who enters the Corrida Colosseum tournament as participant number 13. He serves as commander alongside his brother Boo under Don Chinjao and later assumes full authority over the Happo Navy. Sai becomes known for his mastery of Hasshoken techniques during the battles in Dressrosa and for forming an alliance with the Straw Hat Pirates as part of the Grand Fleet. His actions include defeating multiple opponents in the colosseum and intervening in conflicts involving the Donquixote Family.
Appearance
Sai appears as a large muscular man often seen wearing striped pants and an open shirt during examinations or a black cloak marked with the number 13 on the back while fighting in the Corrida Colosseum. An X-shaped scar crosses his chest when he stands shirtless with fists raised in a defiant posture. He carries a long staff at his side in several confrontations and rides a large horned creature while holding a spiked club during charges.123
During physical examinations Sai lies supine on a mechanical table wearing striped pants and an open shirt before being hurled across the room. In later gatherings he wears ornate armor with a ruffled collar while reacting with wide eyes and an open mouth. His determined glare appears when he charges forward with an extended arm delivering an overhead strike.452
Personality
Sai displays a vengeful and accusatory nature when confronting Don Chinjao about failing to protect their little brother and declares that the elder brother's training was insufficient. He screams with rage-filled intent about having revenge for fallen comrades while his eyes blaze with anger during the fight against Kelly Funk. The crowd recognizes this as the true nature of a commander after he defeats the formidable monster with a single kick.6
Sai shows protective resolve when he lunges forward to grab Baby 5 and angrily tells her to stop claiming he was only pretending while rejecting victory by suicide. He orders her as leader to stay calm and accuses the woman of being crazy during their heated argument. Sai remains defiant toward Don Chinjao by yelling at him to quit the dumb action and rejects any marriage alliance with indifference to his future wife.78
Abilities and powers
Sai employs Hasshoken strikes that send opponents flying and crack the arena floor while landing decisive kicks that defeat Kelly Funk in a single blow. He engages Ideo in a close-range striking match showing visible facial injuries before landing a strike that sends Ideo reeling across the ring. The crowd identifies the technique as Hasshoken during these exchanges.910
History
Sai enters the Corrida Colosseum as part of C-block alongside Boo and other fighters including Ideo and Don Chinjao. He intervenes with Boo to halt Chinjao's rampage and protect their objective while landing a kick on Chinjao that causes no visible damage. Sai later defeats Kelly Funk with one kick and shows the true nature of a commander before clashing with Ideo in a dead heat match.116
After the tournament Sai joins the Happou Armada with Boo and Hajrudin to confront Doflamingo alongside Luffy. He ignores talk of marriage alliance while continuing to dote on Don Chinjao and charges on a large creature toward Baby 5. Sai physically intervenes to stop Baby 5's action and later defeats Lao G with his awakened techniques.1213
Sai assumes leadership of the Happo Navy after Don Chinjao hands over authority and freedom from the fiancee arrangement. He attends the Reverie with Rebecca and others where he recognizes her from Dressrosa and offers to share information with Princess Vivi. Sai later charges at Saint Charlos alongside Leo to save Shirahoshi.1415
Relationships
Sai refers to himself as the younger brother of Don Chinjao from Kanokuni and accuses the elder of being pathetic for failing to protect their little brother. Don Chinjao later acknowledges Sai's growth by bestowing the Drill Dragon Drill Nail name and transferring leadership of the Happo Navy to him. Sai calls out to Chinjao as gramps after the elder is struck by Lao G.97
Sai becomes engaged to Baby 5 after Don Chinjao accepts his earlier offer and later marries her in a ceremony covered in the Grand Straw Hat Pirate Fleet side story. He argues with Baby 5 over usefulness and sanity while protecting her from self-destructive actions and rejects any victory achieved through her suicide. Sai declares his intent to ruin Straw Hat plans by defeating executives yet ultimately aligns with them.137
Major battles
Corrida Colosseum
During the Corrida Colosseum tournament Sai faces Kelly Funk in C-block and lands a decisive kick that defeats the combined Kelly-Bobby body in a single blow after using Hasshoken principles to counter the assassins' advantage. The announcer highlights Sai's performance as showing the true nature of a commander while the crowd recognizes the strength of the technique. Sai also engages Ideo from the Central Fighting Club in a dead-heat striking match that draws excited support from spectators who question whether the two represent the top contenders remaining.1617
Dressrosa conflict
Sai defeats Lao G by employing drill nail and drill dragon techniques while yelling insults that call the opponent a young monkey and foolish ape. Lao G mutters in defeat acknowledging Sai's youth. Earlier Sai awakens the secret technique of Hasshoken after bending Don Chinjao's drill head during an exchange that includes Bujiaogen and direct hits from kicks leaving Sai standing afterward.181920
Reverie
At Pangaea Castle during the Reverie Sai and Leo charge at Saint Charlos after the Celestial Dragon grabs Shirahoshi and orders her capture as a slave. Sai asks Mjosgard whether he can hit the target and receives approval before beginning the Hasshoken Secret Art while onlookers yell his name and express shock at the assault on a Celestial Dragon. The confrontation occurs amid warnings that attacking would bring severe consequences yet Sai proceeds with the strike alongside Leo.212223