Chapter 771 is called "Sai, Don of the Happo Navy".
Zoro and Pica continue battling, and Elizabello II comes to help the former. However, Zoro realizes Pica is aiming at something else.
Meanwhile, Lao G beats up Chinjao, while Baby 5 continues her romantic banter with Sai, still thinking Sai is in love with her. Chinjao overhears this and reprimands Sai, who is supposed to have a political marriage with the Niho Navy's daughter. A frustrated Sai swears to defeat Baby 5 to fulfill his oaths and mockingly tells her to die, but Baby 5 aims a gun at her head, glad to kill herself if it would make Sai happy. A shocked Sai tries to stop her from shooting herself, but Chinjao yells at him. Baby 5 remembers her past, when she was abandoned in the mountains because she was a burden on her mother's group, and now is happy that she can be of use to someone. An enraged Chinjao uses Kiryu Kirikugi to attack Sai, but Sai uses Bujaogen to break his grandfather's head. Lao G takes advantage of this and boosts his power to defeat Chinjao, but Sai retaliates and defeats Lao G.
Zoro continues his battle against Pica and is greeted by Elizabello who states he can use his King Punch on the stone giant anytime he wishes. Zoro thanks him but states he needs to save his punch for later. They both dodge Pica's attacks while Zoro tries to figure what he's after.
Meanwhile, Lao G continues to overwhelm Chinjao with a variety of moves revolving around his old age to his advantage with his Joi Ken fighting style. However, Chinjao is more focused on Sai's presumed engagement with Baby 5 than his fight while Sai yells at him for listening to this. Sai yells at him and Baby 5 for thinking he'd get married like that while Chinjao proclaims he's already engaged to Uholishia of the Niho Navy. While this is going on, Lao G hasn't heard a thing and his soul begins to ascend to heaven. However, Baby 5 calls out to him and manages to bring him back to life while he still has no idea what is going on around him. Sai continues to stop Baby 5 from acting like she's his wife and backs away from her. She asks if he needs her and says she'll do anything for him and Sai jokes saying he wishes she'd die, stating he wishes to repay his debt to the Straw Hats. However, much to his shock, she turns her arm into a gun and points it to her head, stating she will do it by his request. As she states nothing brings her happiness but to be useful by someone, Sai tries to stop her, stating he was joking and this is not what he wants.
Chinjao scolds Sai for helping the enemy, stating a leader must be calm while Sai tells him to shut up. Baby 5 reflects on her past on how she traveled with her mother and a group of people that, thinking Baby 5 would be nothing but a nuisance, has her left in the mountains stating she's not needed by her own mother. As Baby 5 prepares to kill herself and Sai desperately tries to stop her. Chinjao interrupts, stating Sai has brought shame to the Happou Navy and prepares to strike with his headbutt. Sai counters with a kick that bends his legendary head stating it's none of his business. He then stops his grandfather from killing Baby 5 and then proceeds to slap her as well. As Baby 5 states she was trying to be of use to him, Sai notes no one has ever said no to her. While the lower members note that Chinjao's legendary head has been bent, the latter begins to cry. While Sai regrets what he did to his grandfather, Chinjao is not angry but proud that Sai has awakened the full power of the Hasshoken fighting skills stating he now bestows Sai the name "Kiryu Kirikugi" unto his martial leg stating he now has the strength to shatter the Ice Continent. He proclaims the Happo Navy is now officially his while admitting since his fight with Luffy his illness has been acting up and his age has caught up with him. Just before he can finish, Lao G, now larger, strikes Chinjao with a powerful punch. As Chinjao lays unconscious, Lao G reveals the true strength of his Joi Ken fighting style, stating he conserves his energy at a younger age with Qiqong technique.
He charges at Sai stating all of Dressrosa are slaves for Doflamingo including Baby 5 proclaiming she is nothing but a convenient tool for the Donquixote Family. He calls Sai a monkey of the Flower Country while proclaiming he will finish him off and take Baby 5 back for Doflamingo. While Baby 5 is hurt by those words, Sai proclaims if he defeats him he will marry Baby 5. Baby 5 is happy to hear this while Sai has managed to deliver a powerful Haki-impeded kick to Lao G's skull using the Kiryu Kirikugi move. Lao G apologizes to the Young Master and is sent crashing down into a crater from Sai's kick while shouting the "G" letter and cursing Sai by calling him a monkey. Sai states "call me Don" while the info box states both Lao G and Baby 5 are defeated.
- Elizabello II offers to help Zoro in his battle against Pica, but Zoro tells him to save his King Punch for later.
- Sai is confirmed to be able to use Busoshoku Haki.
- Sai bends Chinjao's head and because of this, Chinjao gives Sai the title of Don.
- Lao G uses Jio-Ken to increase his muscle mass.
- Chinjao is defeated by Lao G.
- Baby 5's past is revealed and it is revealed that she wants to be needed by someone due to her mother abandoning her.
- Sai defeats Lao G and agrees to marry Baby 5. This leaves her subdued and unwilling to fight anymore.