The Marine is the most basic Terran infantry unit. The Marine is cheap and quick to produce, and can be highly effective in large groups. He is also the only ranged Tier 1 unit. They can extend their range even further with the U-238 Shells Upgrade, and can be equipped with Stim Packs for added damage bursts.
Marines are the first line of defense for most Terran colonies. A majority of them were at one time criminals or rebels who have undergone mandatory Neural Resocialization. Freed from any previous allegiances or ideologies, these fearless men and women are ready to defend Confederate interests with their lives.
The Powered Combat Suit worn by Confederate Marines is effective against most small-arms fire and provides them with full life-support and NBC (Nuclear/Biological/Chemical) shielding for operation in deep space and hostile environments. The C-14 Impaler Gauss Rifle fires 8mm metal “spikes” at hypersonic speeds. The rounds are designed to provide maximum penetration against
all armor types. To preserve both ammo usage and minimize power requirements, the rifle uses a capacitor system to fire in short, controlled bursts.
The Marine's StarCraft 2 model
The Marine has returned in StarCraft 2 and is laregly unchanged. They now have slightly more health and are able to upgrade their health even further by researching Combat Shields.