Giant, nuclear tanks have been such a huge part of Metal Gear's history that they're the basis of the franchise's name. Each title includes at least one of these beasts that could start World War III, and we wanted to get you caught up on these constructions and their dramatic battles before Metal Gear Solid V: Ground Zeroes hits (more on our MGS V cover story here).

Note: This focuses on the main Metal Gears that served as important boss battles in the core series, so you won't see non-canon Metal Gears or friendly versions like the Mk. II in this list.

Shagohod (Metal Gear Solid 3: Snake Eater)

In the Metal Gear timeline, the Shagohod can be considered the first in a long line of death-dealing giant tanks. While it doesn’t walk like future Metal Gears, this beast can reach speeds of up to 300mph thanks to rocket power. And of course, it functions as a nuclear ballistic missile system. Its end comes after an intense boss battle with Volgin at the helm, in which he uses his own electric powers to charge up the Shagohod to take on Snake and Eva. Unfortunately for him, a sudden bolt of lightning takes him out, along with his favorite ride.

Metal Gear Raxa (Metal Gear Solid: Portable Ops)

Raxa is the first-ever Metal Gear prototype. This awkward-looking quadrupedal tank was completed by Sokolov, the architect behind Snake Eater’s Shagohod. Raxa is the next evolutionary step between the tank-like Shagohod and bipedal Metal Gears. The weapon has the power to hover above the ground and fire a volley of missiles. Big Boss destroys the machine in battle when a psychic enemy takes the helm.

Peace Walker (Metal Gear Solid: Peace Walker)

After Snake Eater, Big Boss starts his plans to form his own private military nation. A few things stand in his way, however, like the Peace Walker robot. Also known as the Basilisk, Peace Walker is commissioned by the CIA’s Hot Coldman. He intended for it to act as a nuclear deterrent to nations that would threaten nuclear strikes, but things go unsurprisingly awry. Big Boss is forced to take it out in battle, but certain elements of its programming kick in during Peace Walker’s final moments. Its AI is programmed partially from The Boss’ psyche (it’s confusing), and this part of its “brain” becomes active. In a final “laying down her gun” moment, The Boss’ psyche decides to make Peace Walker walk into the ocean and sink to the bottom, averting nuclear war.

Metal Gear Zeke (Metal Gear Solid: Peace Walker)

During the events of Peace Walker, Big Boss' forces assemble their own nuclear deterrent back at Mother Base. By the end of the game, it’s operational and things are looking good for the future of Militaires Sans Frontieres. Unfortunately, Paz is revealed as a triple agent for the KGB and Cipher (Major Zero), and hijacks Zeke during Big Boss’ battle with Zadornov. She attempts to use it to force Big Boss to rejoin The Patriots, but he refuses and does battle with his own mechanical creation. He eventually disables Zeke, and Paz is flung into the ocean. Ground Zeroes reveals that Zeke is still fully functional.