Full summary. Thanks to redon from MangaHelpers.
Chapter 1003: "Night on the board".
In the cover, a scorpion gives Reiju some cactus flower.
Chapter starts with Luffy punching Kaidou with many powerful punches. Kaidou spits blood from his mouth, even Big Mom seems shocked. Finally Luffy hits Kaidou with his strongest punch and Kaidou falls to the ground.
Then air comes out of Luffy's body. Kid is shocked and thought Luffy got attacked somehow. Law explains it's just a side effect of Gear 4 and Luffy won't be able to use Haki for 10 minutes.
Kid: "So it's a power that comes with a risk, huh? But if all those punches actually work..."
Big Mom attacks Luffy with flaming version of "Hahaba" (Mother Destruction Sword), but Zoro carries him and jump out of the way. Kid and Killer go to attack Kaidou, who's still on the ground, while Law attacks Big Mom with his "Countershock".
Kaidou rises up from the ground and create a tornado, blowing both Luffy and Zoro away. He then chomps on Luffy.
Zoro: "Hey, don't eat our captain!!"
Zoro uses his "Kokujou Oo Tatsu Maki" (the attack he used on Gyojin Island) to create a tornado to counter Kaidou's tornado. One of his slash go through Kaidou's scales and makes him bleed. Kaidou realizes that Zoro's sword has strange Haki because it one belongs to Oden.
Kaidou: "So you want to try using tornado against me?"
Kaidou then uses a new attack called "Tatsumaki Kaifuu" (Twister Destructive Wind) creating a huge tornado with wind blades flying out to every direction. Zoro carries Luffy and run while Kid and Killer deflect the wind blades and Law use his power to warp out of the way.
Cut to inside of Onigashima castle. The battle above the dome creates a huge tremor, sending rubbles raining down on the battleground below. We see Orochi's head, it's still lying on the ground.
We cut now to CP0, they are sitting in one of the rooms in the castle. A woman with an eye-marked paper on her face (probably one of Who's Who subordinates) is playing music for them.
The two CP0 are playing together "Go" (a japanese game on a board) using white pieces to represent the samurai and black pieces to represent Kaidou's army. The samurai has 5,400 men and already lost 400, Kaidou has 30,000 men and already lost 3,000. Each piece on the board is equal to 1,000 men, so the samurai has 5 pieces left and Kaidou still has 27 pieces.
The head of CP0 complains about how their trade partner (Orochi) is dead, and that the banquet has turned into war. But after Doflamingo's fall, the clash between Kaidou and the Worst Generation is inevitable. He also says that if it turns out that 2 of the 4 Yonkou fall together in this fight, the future of the world will be completely unpredictable.
But they don't believe the samurai can win, since this battle won't end even if they take out Kaidou or Big Mom. They also have to deal with the executives (Ookanban). If they are not defeated, the samurai forces can be easily annihilated.
As he narrates, we see Franky and Sasaki fighting, Sanji looking panicked with blood on his head, Nami, Usopp and Tama doing something together, Ulti running, Jinbe fighting and Yamato preparing to fight with Momonosuke and Shinobu behind her. The head of CP0 ends his talk.
CP0: "Just crush each other as much as possible, pirates."
Cut back to the roof of Onigashima. Before Luffy, Law and Kid, Kaidou finally transforms into his human-beast form (or hybrid form). We see his silhouette standing in the smoke with Big Mom next to him. Kaidou's hybrid form is huge, like twice as tall as Big Mom.
Kaido: "Hey, Linlin! This is getting pretty fun!! Worororo!!"
Big Mom: "Mamamama! Yeah, Kaidou!! I'm feeling exactly the same thing!!"
End of chapter. No break next week.