Terran's Bio Units In Starcraft 2

1. Marine

Marines are the first line of defense for most terran worlds in the Koprulu sector. In the time of the old Confederacy the vast majority of marines were criminals or rebels who had undergone mandatory neural resocialization. Freed from any previous allegiances or ideologies, these fearless soldiers stood ready to defend Confederate interests with their lives. The intake of "resoc" marines has been scaled back in many places since the fall of the Confederacy, but remains a common practice, for there are seldom enough volunteers for the job.

2. Reaper

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.

3. Ghost

Ghosts epitomize the height of terran evolution and physical conditioning. Born with incredible psionic potential, these individuals are recruited and quarantined for government training from childhood. Ghosts channel their psionic energies to augment their natural physical strength and endurance. This process is enhanced by specialized skin-suits worn by ghosts that are laced with a form of psi-sensitive artificial muscle fiber. Thus, a typical ghost is tougher, stronger, and faster than even a well-trained but otherwise average terran.