M9 Gernsback is not a person but a highly advanced Arm Slave (mecha) featured in the anime series Full Metal Panic! Designed and operated by Mithril, an anti-terrorist private military organization, the M9 Gernsback is piloted by key characters such as Sousuke Sagara and Melissa Mao. Its advanced stealth and combat capabilities make it a crucial asset in battles throughout the series. The M9 Gernsback plays a central role in both offensive and defensive missions, symbolizing Mithril's technological superiority.