Chapter 1001 is titled "Battle of Monsters on Onigashima".
The fight between the five Supernovas and the Emperor duo of Kaido and Big Mom begins in earnest, with Luffy managing to withstand Kaido's Raimei Hakke strike and Zoro using Kitsunebi-ryu to cut Prometheus in half. After Zoro and Killer launch a combined attack against Kaido, Luffy, Law, and Kid follow up with powerful simultaneous attacks of their own to drive the Emperor to the ground. Afterwards, Kaido transforms back into his dragon form and takes to the air to face the Supernovas alongside Big Mom on Zeus.
Big Mom yells at Luffy for his declaration, saying he doesn't know what it means to be Pirate King as Kaido gets back up, realizing that Luffy's attack, actually did hurt him. Zoro and Kid are surprised to see his punch work and Killer says that they might actually have a fighting chance. Kaido, however, wonders what happened after he defeated him back in Kuri since he only knows a few people capable of fighting him. In that moment, he sees the shadows of Oden, Whitebeard, Shanks, Roger, and Rocks behind Luffy, and he gives a smirk.
Luffy uses his Kenbunshoku Haki to forsee Kaido's Raimei Hakke, but it moves too fast and Luffy still ends up getting hit, though he is able to stand this time, which Kaido admires. Big Mom tries to use Prometheus to attack Luffy, but Zoro ends up using Kin'emon's Kitsunebi-ryu to cut Prometheus in half, which causes the homie immense pain. As Prometheus reforges, Zoro reminds Luffy that they are fighting two Emperors of the Sea, so they can't afford to drop their guards. Before Kaido can strike Luffy again, Law uses Shambles to save him, bringing him closer to him. Afterwards, Law yells to Luffy that he had already planned on using his powers to move the samurai below, but when Luffy told him to do it, it made it look like he was following his orders, but Luffy retorts that it doesn't matter. Kid takes the opportunity to mock Law calling him Luffy's subordinate, which he vehemently denies, but he calls them both losers which annoys the both of them.
Big Mom has Prometheus fire three balls of fire which she calls "Heavenly Bon-Bons". As the fireballs got closer, Luffy says that whoever reacts to the fireballs first is a loser. Law and Kid refuse to play that game, which causes Luffy to call them losers. This, however, causes all three of them to try to dodge but they get struck, much to Zoro's annoyance. Kaido demands Big Mom stay back while he sees their strength as Zoro tells Killer not to get in his way, calling him "Kamazo" due to recognizing his laughter. Killer retorts that if was using his "Punishers" back then, he would have beaten Zoro, but he doesn't believe him. They both attack Kaido, who praises them for their strength, though Zoro realizes he needs to release more of Enma's power.
Luffy, Law, and Kid get back up as Luffy goes into Gear Fourth, Kid creates a huge suit of metal with Punk Rotten, and Law prepares a Room. Kaido laughs and calls the three of them monsters in their own right, as Luffy punches Kaido with Gomu Gomu no Kong Gun, and Kaido gets crushed by Kid's Punk Vise, and gets several rocks dropped on him by Law's Tact.
After a brief moment, Kaido emerges from the rubble in his dragon form and joins Big Mom in the air riding Zeus and Prometheus covering Napoleon. Kaido tells the five pirates that it would be a shame for him to kill all of them but he has no choice. He and Big Mom also plan on taking their crew, treasure, and Poneglyphs, and that whoever wins this battle will become one step closer to becoming the Pirate King.
- Luffy, Zoro, Kid, Killer, and Law begin fighting Kaido and Big Mom in full force.
- Zoro recognizes Killer as "Kamazo" because of his laughter.
- Killer's scythe weapons are revealed to be called "Punishers".
- Kaido decrees that whoever wins this fight will be much closer to becoming Pirate King.