Chapter 684

Smoker and Vergo trade opening blows in the SAD room, the commander blocking a jitte strike with his bamboo cane before firing an explosive blast from it. Smoker goes intangible to dodge and lands a heavy punch that sends Vergo crashing down. Elsewhere, Sanji and Tashigi flee through the burning B-block until a chemical tank bursts, tearing the wall open and letting Shinokuni claim more of the wounded Marines.

From Vegapunk's old room in section R, Caesar orders the C and D gates closed to funnel everyone into a single corridor rigged to flood with gas. He weeps a self-serving speech to his loyal subordinates, claiming he tried to stop Vegapunk's disastrous experiment four years earlier and only built this gas to prove himself the world's greatest scientist.

Smoker displays the ability to harden his fists much like Luffy's Armament Haki. A flashback exposes Caesar's lie: he was the one ordered to halt his weapon because it endangered the island's people, and when Vegapunk relieved him from the science team for his recklessness, Caesar slammed a console button and triggered the catastrophic blast himself. In the basement garbage dump, Luffy stumbles onto a small dragon that speaks, and the creature asks who he is.

Caesar's true plan is to herd his enemies into area R and release Shinokuni through its outside ventilation shaft. His false version casts Vegapunk as the villain of the prior incident, while the flashback shows Caesar dismissing civilian lives as a necessary sacrifice. Pandaman makes hidden cameos. The cover continues the Caribou Pirates' brawl with the G-5 Marines.