Chapter 870 is titled "Parting".
The Stories of the Self-Proclaimed Straw Hat Grand Fleet: Vol. 7, Bartolomeo Arc: "First off, we'll take down the greatest evil at the port."
Bartolomeo takes down the leader of a rival gang as he and his crew raze the town they arrived at, forcing the rest of the gang to surrender.
Bege finds himself under attack by Big Mom, with the rest of her crew lying in wait. He comes up with an escape plan to turn back human and have Caesar fly him out, and the Vinsmoke Family heads out to distract Big Mom in order to get rid of their debt with Sanji. As the plan is initiated, Big Mom overwhelms Reiju with her opening attack, causing both Luffy and Sanji to come out and clash with her.
Big Mom yells for Bege and Luffy to show themselves, and in desperation Chiffon tries to get Big Mom to spare them for her and Pez's sake. However, Big Mom only grows angry due to seeing Lola's face in her, and continues her attack on Big Father, pointing out that Chiffon is also an accomplice in the assassination plot. As Big Mom attacks, her crew stands outside, preparing to attack the enemy alliance once Bege dies in order to make them an example to the world. Inside Big Father, Bege continues convulsing as he receives injuries from Big Mom, saying that her punches easily break through Big Father's fortifications that is resistant to cannonballs. Luffy tries to run out and attack Big Mom, but Nami has Chopper hold him back. She points out that they have successfully achieved everything they came to do, and tells him to think of a way to escape so they can get to Wano Country.
However, Luffy is concerned for Bege, and Bege admits that he would be willing to bring down his allies with him, but is definitely not willing to let his crew, wife, or son die. He comes up with a plan, where he will turn human, have Caesar exit his body, and have Caesar fly him out of the venue. Caesar immediately rejects the idea, calling it suicidal due to the prevalence of armed Busoshoku Haki users in the venue that could easily shoot him dead. Meanwhile, Judge asks Sanji why he rescued them, and Sanji replies that his father would be saddened to see him holding on to a childhood grudge and laughing at his blood relatives' death. Sanji does not want to live a life where he could not face his father, and he states that the Vinsmoke Sanji who left the Germa Kingdom died 13 years ago, just as Judge wanted; he shouts at Judge to accept that the two are no longer father and son, and to no longer appear in front of them again. Judge obliges, promising to not come near Sanji or the East Blue ever again.
Meanwhile, Caesar argues to Bege that this plan goes beyond what he had agreed to do, and Bege retorts that Caesar will die too if he does not help. Suddenly, Judge tells Bege to open the gate, saying that the Germa will escort the alliance as they make their escape. Caesar is appalled by Judge butting in, and Bege obliges due to the Vinsmokes being capable of flight. Luffy tries to help as well, but Sanji stops him as the Vinsmokes head out, intent on getting rid of their debt to Sanji. Bege finally gets Caesar to act by squeezing his heart, and Caesar rushes out of the fortress along with the Vinsmokes as Bege transforms back into his human form. The Big Mom Pirates immediately open fire as they see this, but the Vinsmokes block their bullets. However, Big Mom also responds by throwing Prometheus at Caesar and Bege, and Caesar flies away from the explosion in a panic. The explosion strikes Reiju, which her brothers do not pay any mind to, and as she gets up, Big Mom decides to attack her first. However, Luffy and Sanji suddenly appear from Bege's body and counter Big Mom's fist, to Reiju's shock. Luffy argues with Sanji, who wanted to be the only one going out, and the rest of their crew is appalled in fear as they watch the two of them take on one of the Yonko.
- After Sanji once again disowns Judge as his father, Judge promises not to interfere in Sanji's life nor go near East Blue again.
- Judge and Caesar know each other in the past.
- Bege deactivates his Big Father form.
- Luffy, Sanji, and the Vinsmoke Family engage Big Mom in combat while Caesar helps Bege and everyone inside him escape the venue.