Hilde Garn is the main villain of Metal Slug: 1st Mission and Metal Slug: 2nd Mission.
Hilde Garn is a colonel in the Regular Army and commander of the Phantom Squad, a weapons smuggling ring working under the Rebel Army. An expert at guerrilla warfare, he's been working together with Lieutenant Colonel Macba to amass a large arsenal of weapons, which included the top secret SV-001 prototype tank from the Regular Army. The Regular Army gets intel of the situation and, fearing the Rebel Army could launch a coup d'etát, employs the services of the Peregrine Falcons, sending a soldier on a covert mission to find the weapons, destroy them and capture Hilde Garn. Though the operation is a success, Hilde Garn escapes and is declared MIA.
This would not be the end of the Phantom Squad, however. One year later Macba would lead the squad and begin a new insurgency, at the same time that rumors began spreading about the Rebel Army having allied themselves with aliens. Hilde Garn himself was the one responsible for contacting the aliens, beginning the development of new weapons with the aliens technology. The Regular Army then send in two soldiers on a new operation, both to stop the insurgency and stop Hilde Garn's plans. Hilde Garn is found on his secret base, where he planned to launch a rocket to reach the Mars People's leader directly, but it's launch is stopped and he ends captured.