From the websites:
The Tsan Ra are a race of aliens that are also part of the Isorian Senatex. The Isorians’ advanced hybrid human-alien technology is partly derived from the bio-silicate interface spores of the Tsan Ra’s ancestors, the warlike Tsan Kiri. Their forebears fought a long local-space war against the Isorian Senatex before abandoning their worlds and fleeing none know where.
Isolator or Isoshields are a kind of forcefield bubble that is selectively permeable to the atmosphere, temperature and nanosphere where present. Large, static devices can create isolation zones encompassing entire buildings. Smaller, mobile machines have a correspondingly smaller field size. Isodrones are general purpose drones fitted with mobile isoshield generators.
There are any number of situations that the IMTel of the Panhuman Concord deems too dangerous for human troops. Admittedly the military shards of the C3 have some discretion to override the extremes of riskaversion that dominate the Concord’s civil shards, but even so, there are many reasons why some ventures must be undertaken by machines.
Tsan Ra Command Squad + Tsan Ra Torus Squad Source
Isorian Iso-Drones Source
C3 Drone Commander + C3 Iso-drone Source