Chapter 1003 is titled "Night on the Board".
Cover Page Request: "Reiju receiving the affections of a scorpion with a cactus flower." PN Noda Skywalker
After successfully pummeling Kaidou with more attacks, Luffy's Gear Fourth expires, forcing Zoro to take care of him as Kaidou and Big Mom unleash attacks of their own. Zoro launches an attack against Kaidou and manages to successfully cut him, which Kaidou then realizes that Zoro is using Oden's sword. Meanwhile, CP-0 is in a room in the Skull Dome, having been invited to the Fire Festival banquet; they keep tabs on the numbers of both sides and how many have fallen. Back on the roof, Kaidou enters his human-beast form and tells Big Mom that this battle is fun.
Luffy finishes pummeling Kaidou with Gomu Gomu no Kong Gatling, knocking him into the ground as Big Mom watches in horror. After finishing, Luffy deflates and returns to normal and lands on the ground as the others watch. Kid asks when Kaidou managed to strike him, but Law explains to Kid that what he is seeing is a side effect of Luffy's Gear Fourth form, and now he won't be able to use his Haki for ten minutes. Kid acknowledges the cost of that strength, but as long as it did some damage to Kaidou it wouldn't matter.
Big Mom laughs if that was the extent of Luffy's strength and uses Haha no Hi to attack him. Zoro, however, manages to grab him and save him from the attack as Big Mom demands he hand him over. Kid tells Killer to keep up the pressure on Kaidou as Law gets close to Big Mom and uses Counter Shock to damage her. Kaidou gets back up and sees Kid and Killer charging for him, and unleashes Tatsumaki to blow everyone away. Zoro comments that Kaidou is practically a natural disaster as he loses his grip on Luffy, who flies into the air and gets chomped on by Kaidou. Angry, Zoro demands Kaidou release his captain as he unleashes his Kokujo: O Tatsumaki on Kaidou, forcing him to release Luffy while getting damaged in the process, which surprises Killer that he actually pierced through Kaidou's scales. Kaidou, who sensed the strange Haki he felt from before again, finally deduces that Zoro was using Oden's sword, as the pain felt similar. Kaidou decides to take on Zoro's twister challenge and unleashed a stronger variation of Tatsumaki called Tatsumaki Kaifu, which everyone tries to dodge.
Inside the castle, CP-0 is revealed to also be attending, though they were disappointed by the sudden death of their business partner Orochi and that the banquet had devolved into a battlefield. They deduced that this was a result of a grudge the samurai held on Kaidou for twenty years. But with Doflamingo gone, a clash between the Worst Generation and the Four Emperors was unavoidable. So the samurai joining the pirate's side was no surprise. CP-0 say that if two of the Four Emperors fall, there is no telling what will happen in the World, though they feel it is of no concern. One of their entertainers informs them that of the 5,400 samurai, 400 have fallen, whereas of the 30,000 Beasts Pirates, 3,000 have fallen. As CP-0 keep record with a go board, they admit that the samurai's sneak attack worked since any other method would have failed. However, just killing Kaidou won't be enough; they have to defeat all of Kaidou's officers to truly win this battle. CP-0 say that the pirates should just try to wipe as much of the other side out as they can.
Up on the roof, Kaidou changes into his hybrid form as he tells Big Mom that this battle has started to get fun, which she agrees with.
- Luffy gets worn out from using Gear Fourth, requiring Zoro to protect him.
- Law deals a blow on Big Mom.
- Zoro manages to deal a significant cut to Kaidou's body, bypassing his scales.
- Kaidou becomes aware that Zoro is using Enma.
- CP-0 is present on Onigashima during the raid.
- The Ninja-Pirate-Mink-Samurai Alliance has 400 casualties while the Beasts Pirates have lost 3000.
- A silhouette of Kaidou's hybrid form is shown.