- "Uhh... those aren't drones."
"Shit... looks like they upgraded."
"They're called Theron Guards."
"You think they know what we're doing?"
'Well, we're not here to sell cookies... So they know something's up."
- —Cpl. Dominic Santiago, Sgt. Marcus Fenix and Pvt. Damon Baird, after spotting Theron Guards
The Theron Guard was an organization of the Locust Hordes' military which represents the elite of the Locust, the head-and-shoulders above the lowly Drones in terms of equipment, intelligence, and training. They are elite Locust troops, assigned to commando-style raids against high-profile targets and high-level defensive missions that require the sort of precision the Therons possess and can handle. Some members of the Theron also act as field officers, leading the lesser Locust troops into battle. If the Drones and Boomers represent the Locust military's hammer and anvil, then the Theron Guard is most decidedly its scalpel.
Therons are easily recognized from other Locust: they wear heavy body armor that covers more of the upper body than drone armor and a long, leather-like strip of material hanging from the back of the waist that trails behind them as they move and gives the impression of a trench coat combined with armor. Many wear distinctive-looking helmets as well, often heavily embellished. Theron Armor is laced with bright red flecks, presumably to give them a more-imposing appearance. Their voices are sibilant and with a definitive, whispering hiss, giving them a distinctly menacing presence. Though it is more intimidating, the hissing and whispering can be a big give away to the opponent of your position. The more higher-ranked Therons are called Theron Sentinels and serve as Sergeants in Theron Guard battle groups. Theron Sentinels are slightly taller, wear a slightly deeper shade of red armor, and have a round helmet with no visible eye slits. The differences in visible appearances are minimal and easily overlooked in the heat of combat, but so are their status upgrades.
Therons usually operate in small squads, led by a Theron Sentinel that serves as a Sergeant, though this is not always the case. They clearly outrank both Drones and Boomers, and can be seen ordering both Locust subspecies around - in several scenarios you can encounter a single standard Theron leading a squad of Drones. They can also be found making use of Bloodmounts and Reavers. As elites, Therons are more powerful, intelligent accurate with their weapons and better-armored than their contemporaries - and they are invariably better armed as well, making them a significantly greater threat than the lesser, rank-and-file Locust troops.
Most Therons use the Torque Bow as their weapon of choice. Because of this, they are a deadly threat capable of instantly killing an unprepared Gear from a considerable distance. They also make use of the Lancer Assault Rifle, Hammerburst Assault Rifle, and Gnasher Shotgun, as well as the Boltok Pistol. Unlike Drones, Therons are smart enough to make use of dropped weapons - so if an allied Locust dies in their presence, they may raid their corpses for weapons or ammo (so if you were to drop a Grenadier with a Theron around, watch for the Theron picking up and utilizing the fallen Grenadier's Bolo Grenades or Shotgun, and so on).
As elites who have better intelligence with better military training, Therons make extensive use of cover and ambushes, and are smart enough to know when a battle is turning against them. Expect them to flee rather than die if they take too much damage, and for other Locust to aid the Theron if they become injured. They frequently send Drones and Grenadiers forward as cannon fodder and to force Gears out into the open, so they can cut them down to piece-meal with their Torque Bows, Mk 2 Lancers and/or Gnasher Shotguns. They also often feign retreat, in order to lure enemies closer and into pre-set firing positions - be aware of their tricks and don't be fooled.
Therons, as stated before, are first introduced guarding the Imulsion pumping facility as Delta Squad is moving in to detonate the Sonic Resonator in Gears of War 1. The facility has the largest group of Therons in one area (since they are being introduced there), but other Therons do appear several times in later chapters of the game. They are everywhere in Act 4 and appear numerous times again in Train Wreck on board the Tyro Pillar, guarding the Lightmass Bomb - the ones on the Tyro Pillar are presumably members of RAAM's personal guard - almost all Therons encountered in Train Wreck are Sentinels.
Therons wear bulky and heavy armors, as they are mainly recognized as guardians. Therons also have randomized helmets; if you reload your save and head through an area, you'll see that the helmets actually change somewhat.
- Main article: Palace Guard
Palace Guards are a new class of Theron Guard introduced in Gears of War 2. They were first seen in the "Enter the Horde" ViDoc, where they were described as "a crazy, mental, much more bad-ass Theron." They wear ornate helmets, and a brighter, more intense variant of the traditional Theron armor making them "highly visible, but highly deadly." They have been seen riding the new Bloodmounts, which they use as battle-mounts while wielding a Torque Bow. In the Campaign of Gears of War 2, most Palace Guards wield Torque Bows while some others wield Hammerbursts. They can also revive each other very quickly in campaign mode.
- Main article: Cleaver Theron
Cleaver Theron's were encountered during the Destruction of Halvo Bay. They are armed with a Butcher Cleaver and charge into battle and attempt to cut Gears to pieces without hesitation. They run right past cover and don't stop until they're on top of you swinging away with their heavy blades. 
- Main article: Theron Sentinel
Theron Sentinels are small strike force-types among the Theron ranks.
- Main article: Theron Elite
In Gears of War 3, a new variant, the Theron Elite, makes its debut. Its armor, with the helmet being the exception, is identical to the standard Theron armor. Its helmet is similar to a beak in shape. These Therons work alongside the Palace Guards as the queen's personal body guards.
Behind the Scenes
- In the Gears of War 2's DLC and map pack, Gears of War 2: Dark Corners, Marcus and Dom clad themselves in Theron Guard armor.
- Theron Guards were ranked number 3 on Gears of War's "Top 5 Deadliest Locust".
- Theron is Greek for Hunter.
- The Theron Guard does not appear in Gears of War 3 multiplayer however in the character selection menu his profile picture can be seen, but when you play as the character it appears as the Theron Sentinel
- The Theron Guard makes an appearance as a Theron Elite after the purchase of the RAAM's Shadow DLC.
- In the Gears of War Ultimate Edition Beta, the design of the Theron Guard's helmet has been changed; instead of six slits (three for each eye), these have been replaced with six circulate cutouts: two big cut-outs for the eyes, and two smaller under each of the bigger.
- The same, the Theron Elite is utilizes the same helmet and mask.
- The Theron Guard, and to a lesser extent the Theron Sentinel, makes a unique voice line that is heard when they are charging up their Torque Bow. This voice line can also be heard while charging up a Torque Bow as a Theron Guard or Theron Sentinel in Gears of War multiplayer. They both say "Ssssssssuffer..."