Punk Hazard Arc

This twenty-sixth chapter of the saga sits at the head of the Dressrosa storyline and counts as the third stretch of the manga's latter half. Having just left Fish-Man Island, the pirates answer a desperate radio plea claiming a samurai is butchering a Marine unit, and the signal points them toward a sealed landmass where one side burns and the other freezes.

The island was once a government laboratory operated by the genius Vegapunk, but a chemical disaster four years prior left it a wasteland, its climate permanently warped by an earlier duel between two admirals. It now shelters the fugitive weapons expert Caesar Clown, alongside the freshly appointed Warlord Trafalgar Law and a rowdy battalion of G-5 Marines commanded by Vice Admiral Smoker.

Luffy, Zoro, Robin, and Usopp head ashore and run into talking dragons, the scattered halves of a frozen samurai, and herds of weaponized centaurs answering to a gaseous figure they call their master. Apart from them, Nami, Sanji, Franky, and Chopper awaken among a crowd of oversized youngsters pleading to be sent home. Bit by bit the crew learns that the children are hooked on drugged candy and used as subjects in a giant-soldier experiment.

Law throws the place into disorder by scrambling people's minds and wrecking the Marine warship, while his real goal, sabotaging the chemist who supplies an Emperor, slowly emerges. Caesar releases Smiley, a poison blob that mutates into Shinokuni, a gas that petrifies and slays anything it reaches, broadcasting the slaughter to underworld brokers as a sales pitch. Caught between the advancing death cloud and Caesar's troops, Luffy proposes a pact with Law to bring down one of the Four Emperors, Kaidou.

The merged pirates and Marines storm the complex, sprinting for its lone sealed gate while shielding the children. Zoro and Tashigi topple the harpy Monet, Smoker and Law trade blows with the treacherous Vice Admiral Vergo, and Chopper struggles to stop the withdrawal-crazed kids from a lethal overdose. Luffy, now immune to toxins, hounds Caesar through three savage rounds and ends him with a Haki-charged strike, unmasking the scientist as a killer before his own people.

Law carves Vergo and the laboratory itself in two, cutting the SAD supply that fed Kaidou's artificial Devil Fruits. Caesar is shackled in Seastone and taken captive, the freed children are entrusted to Tashigi for the journey home, and Brownbeard turns himself in for treatment. Wielding Caesar as leverage, Law calls Doflamingo and orders him to resign his Warlord seat, a demand the rattled broker obeys by the following morning's newspaper.

That same paper reveals the alliance between the Straw Hats and the Heart Pirates to the world. An enraged Doflamingo descends on the island, only for the former admiral Kuzan to step in and protect Smoker. With Kin'emon and the dragon-boy Momonosuke now traveling alongside them, the partnered crews set course for Dressrosa, determined to demolish the SMILE factory and erode Kaidou's strength.