The Hero is the main protagonist of Metal Slug: 1st Mission.
The Hero is a member of the PF Squad sent to attack the Rebel Army's Phantom Squad and defeat Hilde Garn. Although not named, the Hero bears an obvious resemblance to Marco Rossi in both his sprites and official art. After clearing the game once, a Heroine can be selected after starting over or selecting S-Continue. She also is unnamed but appears to a be a mix of Fio and Eri.
- The Hero makes a cameo appearance in the intro of Metal Slug: 2nd Mission as part of a recreation of the first game's ending.
- Red Eye is sometimes considered to be the Heroine. This is despite the fact Red Eye mentions her mission in Metal Slug: 2nd Mission being her first one.
- Special Marco in Metal Slug Attack is based on the Hero's sprites (who wears a blue vest).