Terran Alliance Marine Corps troops traditionally operate in 6-man squads, comprising of 5 enlisted marines plus an officer. Each squad member has their own distinct role within the squad: Technician, Demolitions, Mechanic, Medic, and Scout. The officer (a Squad Captain, usually) is trained in the basics of all roles, in addition to the art of command. Originally, Marine squads operated more like shock trooper units, operating either on their own or in conjunction with "more traditional" ground forces such as the Army. However, over time the Marine Corps has gained sufficient numbers to operate as a ground force in their own right - in more recent deployments squads are deployed alongside other squads, sometimes with specialized squads such as a Medical or Fire Support squad. Squads are either deployed via orbital drop or via dropships.

The Hellcat is a species of large felinoids native to Tau Ceti e. These lizard-like creatures are masters of stealth, equivalent to a nastier version of an Earth lion or tiger, and hunt elementals for food. They typically dwell in caverns with active lava rivers, and can be found basking in the warmth of a lava flow when not actively hunting. Hellcat hunting is a well-appreciated pastime amongst Hands of Action, however overhunting of the creature has lead to a one-kill per year limit for hunters in modern times.