Combine

The Universal Union, the Union, or the 'UU', are used to represent both current Earth & the extradimensional alien empire that had conquered Earth (and many similar realms previously), processing & taking all technological advancements and resource from Earth and installing a new alien-operated technocratic society all over Earth. The Earth was defeated in less than an afternoon, in the "Seven Hour War", which occurred after the Portal Storms triggered by the Black Mesa incident with the Xen dimension being opened, which had triggered the series of events for the Combine to take note of Earth, subsequently leading to a conquest.

The Universal Union comprises the following main factions: Civil Protection, Overwatch Transhuman Arm, Civil Administration Board, Civil Worker's Union, and of course, the Civilians.

The Civil Protection are both protector & prosecutor in the cities they are assigned to. They have ultimate power without any governing authority besides SqLs, DvLs, the CmD, or Dispatch.

The OTA are mindless, brainwashed cybernetic human hybrids with most free-thought processes, e.g. emotion or free will, and non-essential bodily systems, e.g. digestive (they have a side intake valve for nutrient paste injections) or reproductive systems, etc. To demonstrate any free will or mental immaturity as an OTA unit would be Fail Roleplay & should be ashamed for completely ruining both the image & reputation of the OTA's fierce-some lore and potential, with their petulant mingery. They have literally been created to be absolutely subservient drones of the Union. They must not refuse any orders given by their LDRs, SqLs, DvLs, the CmD, or Dispatch. Any insubordination or hint of free will, must & will be met with immediate deservicement without any hesitation. OTA have no rights. OTA do not command. OTA listen & take orders. Simple as.

The Civil Administration Board are the front-face of the Cities they represent. They are like mayors, but without any real power. They perform public events & moral boosting speeches, e.g. reading letters or talking to civilians in public, but hold no actual authority within the Universal Union. They may be declared defunct, deserviced, and replaced, for little to no absolute reason; they are puppets, merely so.

The CWU represents the Union's loyalist-based public sector; offering commercialization or medical specialization of services to their Cities.

The Civilians have no rights. They are mere resources, to be oppressed & crushed under the mighty heel of the Union. They are coerced to join the Civil Protection or induced forcibly as Stalkers or the Overwatch Transhuman Arm.

In terms of simple hierarchy, the UU chain of command is as follows:

Combine Advisor, Dispatch,

the Commander, Division Leader(s), Squad Leader(s),

regular Civil Protection units,

Civil Administration Board,

Overwatch Transhuman Arm (soldiers without rights or free will and are mindless & brainwashed cyborgs),

CWU,

...and Civilians.