CLEO is a presumably military or paramilitary organization which appears in State of Decay: Year One Survival Edition. Little else is know about CLEO, and no CLEO personnel directly appear in the story. CLEO's appearances are limited to regular supply drops over Trumbull Valley, containing Food, Medicine, Weapons, Ammunition, and Construction Materials. It is not clear whether these are intended as emergency supplies for survivors or intended for some possibly deceased group of operatives. Cleo has access to a number of powerful custom weapons.
CLEO uses specialized packages dropped from aircraft containing supplies and marked with a radio beacon to allow them to be located. These beacons produce an audible signal, and thus often attract Zombies, including special infected. It is recommended that the player bring heavy firepower when attempted to retrieve one, particularly later in the game, when these crates are more likely to attract Bloaters or Juggernauts, which cannot be effectively dispatched by running them over in a vehicle.
- CLEO Machete- A more durable Machete, presumably designed for combat.
- CLEO Trench Tool- A military entrenching tool or pickaxe.
- CLEO Wrecker- A large, heavy demolition tool consisting of a Splitting Maul-like blade with a hook on the back.
- CLEO CRA-B- also known as the cranial breacher, a blunt instrument vaguely similar to a medieval flanged mace.
- CLEO Axe- A more durable and deadly hatchet.
- CLEO Striker 40- A .40 caliber firearm, appears to be a Heckler and Koch USP with a muzzle compensator and red dot sight.
- CLEO Revo C- A .357 revolver, appears to be a Safari/Chiappa Rhino with a red dot sight and compensator.
- CLEO PDW- A .45 submachine gun, appears to be a Super Z with an elongated barrel and scope.
- CLEO Revo Shotgun- A combat Shotguns with a six-shot "revolver"-style chamber.
- CLEO HCQB- A stockless close quarter assault rifle similar to a LAR-15 with a scope.
- CLEO LSW- A scoped Mark 46 (Special Operations variant of the M249 SAW. Very high rate of fire.
- CLEO GL40- A 40mm grenade launcher with three-shot magazine and scope.