The Combine are a very powerful interdimensional organization, composed of allied and enslaved species. Their goal is to build an interdimensional empire known as the Universal Union and dominate the Multiverse.
Their military is made up of mostly Synths (enslaved/allied species transformed into bio-engineered weapons.) and the Overwatch. (Police, Soldiers.)
When the City 38 Citadel was destroyed, all of them became isolated units, leaving all earth units to die out and leave their technology behind.
In the case of West Owl, they managed to save most of the Synths and use them for their own military, along with the weapons and the Citadel.
(Note that all concept art used is from Valve, or just random internet people... I do not own anything!)
The Strider's body is covered in a smooth brown carapace or exoskeleton. On the "head" of the Strider is a rapid-firing pulse cannon, with a heavier warp cannon suspended below. The three long legs of the Strider are tipped with sharp spikes and a rosette of finer, hair-like spines.
Very odd Synth, this is used as a scanner to locate enemies. It assists Scouters to hunt down its enemies, and are defeated easily, as they don't have any defenses.
They can be modified for other reasons like spying on citizens or "suicidal" exploding.
They are very slow, but can resist in varied enviroments.
This synth is a small, crab-like synth with a Combine Rocket Launcher mounted on its back. They serve as back- ups if the main units are down.
They are quick, and have heavy armour. They are resistant to explosives but can be killed using them.
More of a bot than anything else, this carrys a Pulse Sniper Rifle, and is engineered for stealthy reasons. Not much is known about them.
They are very stealthy, and are accurate. They also have enhanced vision, and are very good and locating enemies.
They are also equipped with armour, that is bullet proof.
They can sometimes be seen using rocket launchers.
Like other Synths, Gunships are living creatures that have been artificially altered and augmented with Combine technology.
They are powered by an array of jet engines on their underside, and maneuver using a rear-mounted rotor with insect wing-like blades. Compound eyes that bear a close resemblance to those of a dragonfly are positioned directly behind the Gunship's pulse gun. In addition, the chassis itself has one large exposed compound eye on either side, which is assumed to be used to detect enemies under normal conditions.
These are synths that use their sharp claws to kill. They run quickly, and are very stealthy. Since not much is known about them, it probably means they are not common.
They sometimes have weapons, but usually go without any. They will sometimes jab with their sharp claws. They are able to jump very high, and survive high falls.
They have artificial eyes, which enhance their vision.
They always appear in secret missions, only if the ESS (Elite Stalker Squad) is unable to defeat the designated rebel base.
They are very easy to avoid, but not outrun.
CPs are typically armed with OSIP's and Stun Batons. In more critical circumstances, they will use OSISMG' and Emplacement Guns, and will be provided with fire support from APC's and Hunter-Choppers. Some officers may be armed with a deployable Manhack and possibly a Flare Gun to call for help. CPs are known to beat unarmed Citizens with Stun Batons at the slightest provocation..
These are usually used for guarding important places that belong to the combine. They have high-preformance weapons and they are more well trained. They are usually equipped with the same weapons as the normal overwatch soldiers, but have better armour and more ammunition. Unlike the normal overwatch soldiers, they are completley synths.
They are not too quick, but are very skilled at "hand" to hand combat.
Dropships by themselves are unarmed and as a result, they don't attack the enemies. However, the containers typically carried by Dropships sport a mounted pulse turret on the front, designed to suppress any opposition in front of the synth, allowing the occupants to deploy safely.
Dropships are very useful aircraft for the Combine, being able to quickly transport Combine Soldiers, APCs, Striders, and Civil Protection officers to where ever they may be needed.
They are special Combine-Modified Human technology that is used in special occasions when it is needed.
They can send down tons of bombs, seemingly more than they can handle
They are piloted by 2 Civil Protection units, which 1 is the turret operater, and the other is the piloter who controls the rest of the helicopter. It is very resistant, due to the combine metal used in building it.
The Combine APC is a vehicle used by the Combine as transport.
They can also be used for combat, being equipped with a rocket launcher and small turret.