Metal Gear ZEKE

Metal Gear ZEKE was a nuclear-armed bipedal tank developed by the Militaires Sans Frontieres.

History
During the 1974 Peace Walker Incident, Big Boss (Naked Snake) and the MSF commissioned doctors Huey Emmerich and Strangelove to create Metal Gear ZEKE. Emmerich supervised the assembly of the frame, and Strangelove oversaw the development of the AI, it was intended to function as an unmanned weapon.

Shortly after ZEKE was completed, MSF subcommander Kazuhira Miller suggested that the nuclear warhead recovered from Peace Walker be used to arm the weapon, with the intention of making it a deterrent against hostile countries opposed to the MSF's fledgling "mercenary nation". However, Cipher agent Pacifica Ocean secretly made further modifications to ZEKE, allowing it to accomodate a human pilot, while her KGB ally Vladimir Zadornov escaped the MSF's custody multiple times, serving as a diversion. Some of the modifications included installing a pilot's seat inside the AI pod, a dual-control piloting lever for operating the legs, a safety restraint, and a water-flooded cockpit (presumably to act as a shock absorbant for ZEKE). In the cutscene featuring Paz/Pacifica piloting ZEKE, she also appears to be wearing goggles and a mask, presumably for the ability to see from ZEKE's point of view (since windows were a weak point and VR didn't exist at that point in time).

Pacifica eventually hijacked ZEKE, with Zadornov escaping the seventh time as a diversion for her to make off with the weapon unnoticed. Big Boss discovered this shortly after encountering and killing Zadornov out of self defense, at the shooting range within MSF's Mother Base. Pacifica attempted to force Big Boss into rejoining "Cipher", the group responsible for the development of the Peace Walker Project. Big Boss refused, so Pacifica decided to use ZEKE to launch a nuclear strike at the East Coast of the United States, which would cause the public to believe that the Militaires Sans Frontieres were an extremist cult. Big Boss was then forced to fight and defeat Pacifica by heavily damaging ZEKE.

After the incident, Strangelove and Huey discussed ZEKE's fate, and Strangelove revealed that she had made a backup copy of its AI, so at the very least, ZEKE could walk. However, whether ZEKE could continue on or not was up to Big Boss. Big Boss also used ZEKE in a mock battle, upon Huey's suggestion, in case someone attempted to hijack ZEKE again. ZEKE was later replaced with TX-55.

Information
Metal Gear ZEKE was created using parts salvaged from the AI weapons of the Peace Walker Project: the rocket boosters from Pupa, the radome and railgun from Chrysalis, the armor from Cocoon, and the legs from Peace Walker, along with head parts from all four. Other than the above listed salvaged parts, various body parts could also be created by utilizing various scrap portions of the AI weapons, of which about five are needed to make each part. In addition to the actual parts, the AI was also made up of memory boards salvaged from the AI pods of the AI weapons. Its legs are also extremely susceptible to damage, and require it to be working under 100% efficiency for it to operate. This also means that even if it is 95% operable, its operability is handicapped.

Its AI, unlike Peace Walker, was not a replica of human thought, and thus not able to make decisions relating to nuclear retaliation. Consequentally, it is also incapable of self-generated speech in its speech synthesis system. However, it was advanced enough to be capable of highly independent action in combat when given orders from a pilot, including protecting infantry, destroying the enemy, and launching a nuke. ZEKE's AI could also be programmed with pre-set messages depending on the situation to make up for lacking self-generated speech, and was also capable of singing, although it could only process and perform lyrics and cannot perform original compositions.

Trivia
The codename "ZEKE" derives from the official Allied Codename for the Mitsubishi Navy Type 0 Carrier Fighter. Its alternate codename is called the A6M Zero.

Behind the scenes
Metal Gear ZEKE's appearance bears a strong resemblance to Metal Gear REX, due to the rail gun situated on its right shoulder, and a radome on the left. According to Hideo Kojima, he wanted something resembling a older version, combined with a newer version of Metal Gear, which would give fans a good laugh, but also give them a good challenge. In addition, it also shares the same Allied codename origin as Metal Gear RAY.

Metal Gear ZEKE, along with the Pupa, Chrysalis, Cocoon, and Peace Walker, utilize the VOCALOID2 software for their dialogue. Like the other AI weapons,a "Play Arts Kai" figure of ZEKE was released by Square Enix.

Design
Metal Gear ZEKE consists of 4 main parts, namely Head, Power Unit, Walk, and Leg Units, as well as the Railgun. Without these 5 components, ZEKE cannot be used in Outer Ops and will remain stationed within Mother Base.

To obtain scraps for the main parts and optional parts, players must not destroy any of the AI weapon's components, dealing only moderate damage to them. The damage ratio of different components (in %) can be seen in the last tab of the pause menu or by using the Analyser. However, the heads of all AI weapons and the pair of legs from Peace Walker are only acquired in one piece and not as scrap. With the exception of the Head parts, the maximum amount of main parts to assemble/store is three. Head parts have a maximum of five to assemble and/or store. Also, the amount of scrap required to develop the main parts is five.

The head part of all AI weapons can only be obtained during the Custom battle Extra Ops with the exception of the Peace Walker leg which can be obtained not only from the Peace Walker Custom battle but the Peace Walker Type II battle. The various head parts for both ZEKE and the AI weapons are presumably stored in the hangar section of Mother Base.

From time, customization can be done with optional parts taken from the AI weapons for better performance, new weapons or new abilities:

Pupa
Head - Very similar to the head of ZEKE. The two head mounted machine-guns will be replaced with a single electric shock unit. ZEKE can use the electric shock unit to perform rapid fire attacks with lower damage, attack from a distance with moderate damage or maximise the voltage to perform immense damage with increased required charge time respectively with each method. Also, unlike the Pupa, it does not require the usage of lightning rods to perform the maximized high voltage attack. Up to 5 head parts can be collected.

Jet Pack - Grants ZEKE the ability to charge around, dealing moderate damage to anyone caught and one of the hardest attacks to evade. Up to 3 jet pack parts can be collected.

Chrysalis
Head - The Chrysalis head is capable of firing guided missiles which significantly deals more damage and more likely to hit the player than its standard missiles. Up to 5 head parts can be collected.

Radome - The Radome actually grants ZEKE immunity to Chaff Grenades although it is claimed to increase accuracy. Up to 3 radomes can be collected.

Railgun - An electromagnetic weapon which requires time to charge and fire a large ballistic projectile. ZEKE is vulnerable to long-range direct hits as it must remain stationary to fire this weapon. Can deal either heavy to devastating damage. Damage increases and evasion becomes more difficult with increased AI capability. Deals a fixed 6000 damage on up to 2 mechanical targets in Outer Ops. Up to 3 rail guns can be collected. This is also the only "optional" part that is required for ZEKE's completion.

Cocoon
Head - The Cocoon head has a large-caliber cannon as its primary feature. Although it is a direct fire weapon as opposed to Chrysalis's guided missiles, its splash damage makes up for it. The Cocoon head gives ZEKE the abilty to deal 4000 damage on up to 4 targets in Outer Ops using missiles. Up to 5 head parts can be collected.

Armor - Reduces damage inflicted towards ZEKE. Up to 3 armor parts can be collected.

Peace Walker
Head - Grants ZEKE the ability to use the Poison Beam which renders player(s) immobile on contact, known as the poison of the basilisk. The head unit is capable of emitting an electromagnetic pulse which deflects all missiles fired towards it as well as grenades from rifle-mounted grenade launchers. Performs the Petrifying Attack (Petrif. Attack) which deals 4500 damage to an individual target in Outer Ops. Up to 5 head parts can be collected.

Legs - Gives ZEKE an S-mine launcher and enhanced mobility. S-mines launched by ZEKE move in a horizontal direction as opposed to Peace Walker which makes evasion from this weapon much more difficult. Note that 3 Peace Walker leg parts can be stored however it can be obtained from both Peace Walker Type II and Peace Walker Custom.

AI pod
ZEKE is controlled by an AI pod installed on its head. Players can gather memory boards from different AI weapons to increase ZEKE's overall performance. To obtain the boards, the associated components must be damaged during the battle. The player will have one minute to remove the boards from inside the AI pod.

There are four types of memory board, denoted by color:


 *  Mobility  - affects movement
 *  Sense  - affects search capability
 *  Attack  - affects offensive capability
 *  Control  - affects response time

Color
Players can customize ZEKE to various colors, though they are purely cosmetic and does not significantly affect its performance.