MH5

MH5 is a heavily concentrated toxic gas built to disperse rapidly, able to smother an area as wide as an entire settlement in a little more than five minutes. Krieg treats it as the most terrifying instrument he owns and delivers it by way of an explosive round. The label itself borrows from chemistry, matching the notation for a genuine substance, 3-Methylthiophene benzoic acid, which turns poisonous once concentrated.

Krieg usually fires the round from the launcher mounted at the center of his left shoulder plate, and where it lands a dense cloud of poisonous vapor erupts and hangs for roughly five minutes. Anyone breathing it in without a shield suffers sudden organ collapse and bleeding within, and Krieg claims the fumes can end a man's life inside an hour. Contact with the skin alone seems to do nothing, since Luffy came through fully enveloped in it while wearing a swiped mask. Given how deadly it is, Krieg reserves the weapon for a final option and rations its use carefully, even luring enemies with dummy shells so he never risks catching it himself.

The gas is the property of Don Krieg, who turned it loose on the Baratie. As a precaution, he and every member of his crew keep gas masks on hand whenever it comes into play. Wielding this poison, Krieg and the Krieg Pirates have leveled entire villages.