Chapter 766 is called "Smile".
A tribute to Naruto's ending, Luffy eats ramen (Naruto's favorite food) with Chopper on his head and Nami as a waitress with a Konohagakure design changpao at a restaurant. A little fox eating ramen and wearing an Uzumaki sleeveless shirt is seen among them. There's another character sharing Luffy's table, eating meat (Luffy's favorite food) but it is covered by Nami so his face is unseen; however, due to his clothes and size it is heavily implied that it is Naruto Uzumaki himself.
The One Piece logo is different in this chapter, with the O in a Konohagakure symbol shape, the first E holding a shuriken and the classic I in the form of Luffy now resembling of Naruto.
Donquixote Rosinante retrieves the Ope Ope no Mi and gives it to Law, forcing it down his throat. Rosinante falls, beaten and bloody, but gives Law a letter to give to a nearby Marine ship. He runs and gives the letter to the Marine, Vergo, then immediately brings Vergo to Rosinante. Upon discovering Corazon's identity, Vergo calls Doflamingo and his crew to Minion Island. Doflamingo activates his Birdcage and captures all the Marines on the island. As Rosinante nears death, he smiles, wishing his smile to be the last thing Law remembers about him.
On Swallow Island Vice Admiral Tsuru seeing no sign of the Donquixote Pirates, questions Rosinante's intel. She then receives a report from the scouts on Minion island that there was a fire in the lair of Diez Barrels' crew and advises the scouts to find out what happened while remaining discrete since the deal must not be compromised or they will lose the fruit. At the ghost town at Minion Island, Barrels yells at his men to find the stolen fruit if they don't want this 5 billion belly deal to go south.
Rosinante, having sustained significant injuries at his slip-up with the pirate patrol manages to reach Law and presents the Ope Ope no Mi to him. Law asked him about the gunshots and fire but Rosinante dismisses those incidents and tells him that the fruit will save Law's life but Law was skeptical of the fruit's power and doubts that he will be cured. Infuriated with Law's attitude, Rosinante force fed the fruit to Law despite his protest. In the end, when Law swallowed the fruit he yells at Rosinante that he was not psychologically ready to become a Devil Fruit user but instead sees Rosinante collapse face first on the ground. Rosinante, weak from his injuries assures Law that with the fruit he can cure himself and that they outwitted Doflamingo. Knowing that Doflamingo will never stop until he can get the fruit, Rosinante asks Law for a favor that he must do. Confused with Rosinante condition, Law helps turn Rosinante around and was horrified at the numerous gunshots and open wounds on him. Rosinante told him about his blunder with a patrol and assures Law that he will survive this. Law, scared for his friend's life tries to use the fruit's power despite having no experience in it. Rosinante stops him telling that its not like magic and reminds Law of the favor he asked him to do. At the west of the island, there is a Marine spy ship and Law must deliver an intelligence letter to the marines. It is important that the letter reaches them since it will save a kingdom called Dressrosa from Doflamingo's cruelty. Once Law delivers the letter, they will leave the island immediately.
Law manages to find a marine patrol and waits for them to leave. He later sees a lone Marine move by and reveals himself to him, giving him the letter. The man who turns out to be Vergo recognizes the importance of the letter and thanks Law, but Law tearfully begged him to save his friend who was shot. Seeing no other choice, Vergo carries Law to where his friend is, only to be shocked at seeing Corazon here. Rosinante was also surprised and accidently revealed his voice to Vergo. Law was confused at this until he remember Vergo's name being mentioned by Rosinante being one of Doflamingo's officers. Vergo, being suspicious of Corazon's presence decides to check the intelligence letter given to him by Law despite Corazon's protest. Rosinante cursed his bad luck since Vergo was one of Doflamingo's trusted crew members. Once Vergo reads the contents of the letter, he delivers a vicious kick to Rosinante face, no longer calling him Corazon. Law tries to stop Vergo, but the Doflamingo spy was unfazed when he grabs Law in a choking grip. He remembers Law as the kid from Flevance and cruely reminds Law that since he is his superior, he must address him as "Vergo-san" and throws Law away. Vergo was extremely angry at Rosinante's double-crossing and destroys the letter that if given to the marines would ruin the years of planning by the Doflamingo family.
Once his beating of the two traitors was concluded, Vergo contacted Doflamingo and reveals everything he knows of what happened. Doflamingo was mildly surprised at the news of his brother being a Marine spy and that he was trying to bring him down since rejoining the family. Vergo learns that Doflamingo is currently on Minion island since he saw the marines waiting for him on Swallow island and knew that someone ratted him out. Seeing that his own brother was the mole, Doflamingo declares that Corazon is no longer part of the family and orders Vergo to retrieve the Ope Ope no Mi from Corazon since he suspects that Corazon stole it before he arrived. Vergo turns toward the two traitors only to find them gone when he was on the Den Den Mushi. Doflamingo, realizes that they escaped, assures that they won't escape and creates a Birdcage that covers a large portion of the island, preventing anyone from escaping while controlling their every move. Rosinante and Law, barely recovering from Vergo's assault witnessed the formation of the Birdcage and Rosinante knew that Doflamingo will not let them leave that easily. Rosinante knows there is no hope for him but was determined to make it his final mission to save Law from Doflamingo's wrath. He smiles at Law, saying that he'll die smiling, and expresses his hopes that if Law thinks of him when he's gone, he will remember him smiling.
- The cover page pays tribute to the end of Naruto, another series featured in WSJ, which had its final chapter in the same issue. The cover features Luffy eating Naruto's favorite food, ramen.
- The first few characters on the menu papers in the cover art, respectively, spell out ナ ル と おつ カレ 三 で し た (na-ru-to-otsu-kare-san-de-shi-ta). Combining it into ナルトお疲れ様でした (Naruto otsukaresama deshita), which translates to "Naruto, thanks for the hard work".
- The three featured Straw Hats have names beginning with Na (Nami), Ru (Rufī) and To (Tonī), forming "Naruto".
- The Ope Ope no Mi was originally worth 5,000,000,000.
- Law eats the Ope Ope no Mi.
- Rosinante had a secret document that could jeopardize Doflamingo's plan to take over Dressrosa. He wanted Law to give it to the Marines, but Law gave it to Vergo, unaware of his true allegiance at the time.
- Vergo learns about Rosinante double crossing the family and informs Doflamingo.
- When Rosinante recognizes Vergo, he becomes so distressed that he forgets to maintain his act as a mute and accidentally addresses him by name.
- Vergo was surprised to hear Rosinante speaking.
- Vergo then reads Corazon's secret letter to the Marines and figures out he has betrayed the Donquixote Family, shredding it upon realizing it held enough information to finish off the family.
- Vergo already had the ability to use Busoshoku Haki, which he used while attacking Rosinante.
- Despite being the second Corazon, Rosinante was unaware of Vergo's mission.
- Rosinante disappeared from the family at age 8 and returned 14 years later.
- The incident in which Vergo traumatized Law with a severe beating is shown.
- Vergo assaults Corazon to near-death and Law tries to stop him, causing Vergo to also turn his wrath on Law and swiftly knock him out.
- Vergo leaves Rosinante alive so that Doflamingo can take care of the matter of his brother's betrayal personally. He also spares Law.
- Doflamingo and his crew arrive at Minion Island and he uses "Birdcage" to trap Law and Rosinante.
- Rosinante is about to sacrifice himself to save Law.