MH5

The MH5 is a highly potent chemical toxin that can spread quickly and cover an area as large as a village in little over 5 minutes. It is Krieg's most dreaded weapon and is typically employed through the use of an explosive shell.

Effects
Typically fired from the central launcher in Krieg's left shoulder-plate, its impact spreads a large cloud of a powerful chemical toxic gas that lasts around five minutes. The poison inflicts immediate organ failure and internal bleeding on anyone who breathes it unprotected and, according to Krieg, can kill a man within an hour.

With this gas, Krieg and his men have been able to destroy whole villages.

As a precaution for its use, Krieg and his crewmen all carry gas masks. The gas is apparently harmless through mere skin exposure, as Luffy—with a stolen mask—was able to survive with no ill effects even when his body was completely engulfed. Additionally, because of how dangerous it is, Krieg saves it as a last resort, and uses it sparingly, not wanting to risk possible exposure. He is even willing to bait enemies with it, using a decoy shell to trick enemies.