Originally designed by Tokugawa Heavy Industries, the exoskeleton was used by Gray Fox during the Shadow Moses Incident. It provided a shell to which his injured body could be connected permanently. Missing body parts could be replaced with mechanical ones. The suit was also able to provide life support functions.
The appearance of the exoskeleton was a blue representation of a male muscular appearance with red shoulder pads, gauntlets, elbows, knees, and ankles with a white head. It also had a red lamp in the central portion of the facemask, with the eyeslots being to the left and right of the lamp.
Stealth Camouflage - The exoskeleton comes with a built-in stealth camouflage, allowing the wearer to remain undetected even in the center of enemy compounds. The device, however, also demonstrated susceptibility to chaff grenade interference that caused the device to deactivate.
Arm-mounted cannon - Gray Fox was able to mount a cannon onto his right arm which appeared to fire rapid energy bolts, potentially a particle or plasma weapon.
Radar dampening field - The exoskeleton was also demonstrated to emit electromagnetic waves that causes a radar, even one as advanced as the Soliton Radar, to short out should its wearer be in close proximity. This trait was best demonstrated when Solid Snake arrived at the Western labs the first time around, after Gray Fox managed to wipe out the soldiers stationed there, as well as during their fight in the actual lab itself.
Laser vulnerability - Despite the exoskeleton's great durability against physical attacks, it demonstrated vulnerability to laser weaponry: for example, during Gray Fox's confrontation with Metal Gear REX, his arm was cut off by its laser cannon.
Electrical interference - Although the suit was capable of shorting out any radars in close proximity to the suit, another vulnerability of the exoskeleton was its own susceptibility to chaff grenades, which apparently interfere with the suit's power systems, preventing the suit from movemment entirely and thus paralyzing the wearer for a short period.
Discharges - Due to the testing of the exoskeleton's effectiveness, as part of Dr. Clark's gene therapy project, Fox's suit often released painful electrical discharges, at times causing him to demand medicine (during the testing, he was often drugged for several months). Raiden, the third Cyborg Ninja, later stated that a large factor in these discharges were the result of badly-done reconnection of nerve endings.
Behind the scenes
In Metal Gear Solid 2: Substance, VR missions have Raiden wearing Gray Fox's cyborg ninja outfit. In addition, Gray Fox's exoskeleton is also a playable skin in Metal Gear Rising: Revengeance. The design of the Gray Fox model was taken directly from the standard Play Arts KAI standard figure for Gray Fox.
- "A chassis patterned after Gray Fox's body circa the Shadow Moses incident, but functionally equivalent to recent cyborg bodies. Though it was termed an "exoskeleton" in those days before the advent of modern cyborg technology, it could not be taken on and off at will."
- ―Gray Fox description in Metal Gear Rising: Revengeance
- "The high-frequency Blade used by ex-FOXHOUND field agent Frank Jaegar, a.k.a. Gray Fox, after he was outfitted in a cyborg ninja chassis by Dr. Clark. Gray Fox's soul still echoes through the blade, sometimes enabling it to cut clean through enemies, armor and all."
- ―FOX Blade description in Metal Gear Rising: Revengeance
The first description implies "exoskeleton" is a depreciated term for non-removable replacement body parts in the game's universe, with cyborg body having become the standard instead. Presumably "exoskeleton" now only refers to systems which are external to the user's body, such as the suits worn by Olga Gurlukovich and the Beauty and the Beast Unit.