Chapter 863 is titled "The Honorable".
Big Mom watches with fury as the wedding cake she was looking forward to eating gets destroyed by dozens of Luffy clones, who were actually animals made to look like Luffy due to Brûlée's power, which also allowed them to enter the cake via a mirror. Luffy aims to attack Mother Carmel's portrait, but Katakuri finds the real Luffy and traps him in a sticky substance with the power of the Mochi Mochi no Mi. However, Jinbe frees Luffy and takes responsibility for the attack, stating his desire to leave Big Mom's crew even if it costs him his own life. However, Big Mom is unable to pull away his lifespan due to him not fearing her, and attacks him instead. In the midst of the chaos, Brook goes up to the Carmel portrait in a Luffy disguise and shatters it with a hammer.
Three and a half hours ago, Bege reacts in surprise to Luffy's suggestion of putting a mirror inside the wedding cake. Brûlée protests heavily, and Luffy remembers that she can make copies of people out of animals, which Chopper confirms. Luffy then catches several animals for Brûlée to make into copies of him, to her shock. In the present, the wedding guests react in shock to Luffy and his copies flying out of the cake, and Morgans excitedly calls it big news. The guests start to run as the giant cake begins toppling in their direction, and Sanji catches Pudding as he jumps off the cake, placing his trust in Luffy to complete the plan. Smoothie is appalled that Luffy did not die in the Prisoner Library like Mont-d'Or had told her, and Mont-d'Or angrily reflects that Opera lied to him in order to protect himself.
Big Mom then begins to have a crisis as she witnesses the destruction of the cake she was looking forward to immensely. Streusen tries to calm her down, but Big Mom demands another cake before threatening the lives of her cooks. Morgans gets excited to see Big Mom's "Soul Pocus" technique as she removes the lifespans of several cooks, killing them. Meanwhile, in the Mirro-World, the Sanji Retrieval Team gets the last of the Luffy clones out into the wedding venue, and Jinbe and Pedro head out to back Luffy up. Nami, Chopper, and Carrot then head outside as well in order to rescue the Vinsmoke Family, and they leave Caesar Clown behind to do his job, belittling him in the process. Big Mom angrily confronts Luffy and his clones, and wonders aloud which Luffy is the real one. Bege is initially impressed with the bravado of Luffy's plan, but the real Luffy reveals himself to Big Mom, leaving him aghast as Big Mom confronts the real Luffy. Luffy sees the portrait of Mother Carmel and targets it, and Bege has Vito and Gotti get ready to attack Big Mom with their KX Launchers. Nami, Chopper, and Carrot hide inside the wedding cake, preparing to go three seconds after Luffy breaks the portrait and rescue the Vinsmokes.
Big Mom summons Zeus and Prometheus to attack Luffy, and Luffy prepares to attack, but he is suddenly intercepted by a massive tendril composed of a sticky substance. The substance is coming from Katakuri's leg, and Katakuri tells Big Mom that this one is the real Luffy while the others are just animals. Luffy's arms and legs are swallowed in the massive substance, and Big Mom initially gets mad at Katakuri for trying to save her, but Katakuri tells her that he knew Luffy was going after the portrait of Mother Carmel. Katakuri notes that only people close to the family know about the importance of the portrait, and orders Luffy to reveal who told him about it as he sends the Straw Hat falling toward the ground. Bege begins to get worried, and Pedro prepares to free Luffy from Katakuri, but Jinbe steps in and attacks with a massive burst of water, softening the sticky substance and freeing Luffy from it.
Jinbe tells Luffy that Katakuri ate the Paramecia-type Mochi Mochi no Mi and warns him to avoid his sticky substance, before claiming to Big Mom that he was the one who revealed Carmel's importance. Big Mom is not pleased, and accuses Jinbe of starting a mutiny, but Jinbe states that he is simply quitting her crew to join the Straw Hat Pirates, much to Luffy's delight and Morgans' excitement at such big news. Big Mom is fine with that, but must take Jinbe's lifespan in return, and Jinbe is fine with her doing so as long as she does not harm any of his comrades. Big Mom calls Jinbe's desire foolish, and asks again whether he wants to stay or to give up his life, but to her bewilderment Jinbe wants her to take his life, and his soul is not coming out of his body because he shows no fear. The Big Mom Pirates are shocked by his lack of fear, as Jinbe states that he will not cower at a Yonko if he intends to join the crew of the future Pirate King, and offers Big Mom a sake cup to signify his departure if she cannot take away his lifespan. The Straw Hats are amazed by Jinbe's courage and Luffy cheers him on, but Big Mom steps on the sake cup and now recognizes Jinbe as her enemy as she attacks him with Zeus and Prometheus. However, in the midst of the chaos, Brook approaches Carmel's portrait disguised as Luffy, and shatters the portrait with a hammer.
- The details of Luffy's plan to enter the wedding venue are revealed.
- Big Mom's ability to take away a person’s life span only affects those who show fear towards her.
- Luffy and his team enter the wedding venue.
- Luffy sees Big Mom in person for the first time.
- The Big Mom Pirates realize Opera's deception.
- Katakuri possesses a special Paramecia-type Devil Fruit power called the Mochi Mochi no Mi.
- In the Magazine release of the chapter, it was stated to be a Logia, but retconned in the Volume release as a "special Paramecia".
- Katakuri can use Busoshoku Haki.
- Jinbe officially declares to Big Mom that he is leaving the Big Mom Pirates and joining the Straw Hat Pirates.
- Brook destroys the picture of Carmel.