The Terran Reaper is a lightly armored, jump pack equipped infantry unit. It is designed to be a base raider, having it's jump pack to jump up and down cliffs without needing a spotter. It does high damage against light targets, and also throws high-damage explosives at buildings, adding to its base raiding abilities.
Alternatively, they can be used as a scout, both being able to traverse cliffs and being one of the faster units in the game.
Reapers are the most hardened terran criminals, taken from the most dangerous and violent prisons. Potential marines who prove too intractable even after resocialization are instead sent to the "Icehouse" in the Torus system, where reapers are trained.
Reaper troopers are chemically altered to make them even more aggressive before being subjected to weeks of brutal training in close-quarters combat and the use of their jet packs. A reaper who survives two years of duty is granted a full pardon and freed, his debt to society fully paid. In five years of service, the Reaper Corps has yet to have a single trooper survive more than six months.
In combat, reapers attack with dual gauss pistols, the rapid-fire signature weapon of their "strike fast, strike hard" credo. For tougher targets, reapers are often equipped with the dangerously unstable deuterium-eight demolition device, or D-8 charges, as they are commonly known. These can be thrown a short distance and will detonate after an equally short delay. Using D-8 charges is an acquired skill that few troopers live long enough to master.
Reapers are lightly armored and unsuited to head-on firefights. The key to their success lies in their personal jet packs. These packs grant reapers a high degree of mobility, including the ability to scramble up or down cliffs and jump across rivers, crevasses, and other obstacles. Reaper combat techniques emphasize hit-and-run raiding, preferably against enemy structures and workers, so that reapers can inflict maximum damage and then retreat before the enemy can muster a response.
Perhaps unsurprisingly reapers are also enthusiastic users of stimpacks. The dangerous cocktail of combat enhancement chemicals suits their high-speed tactics perfectly, and the long-term side effects are scarcely likely to prove an issue.