The Metal Head nest is a vast wasteland home to the Metal Head race featured in Jak II. As such, a heavy concentration of rare types of metal heads may be found here such as the grunt elephant and flying spider, among others. The nest is also home to Mar's gun, as the legendary figure Mar intended to use it to penetrate the primary part of the nest before his death. The nest itself is located inside a large mountainous structure, surrounded by metal and concrete scaffolding possibly reminiscent of a past civilization.
Before the events of Jak II, Baron Praxis led the Krimzon Guard through an assault on the nest, after which he sustained serious injury to the left side of his face, his nose, and his cranium. Numerous Krimzon Guard security tanks, presumably from the battle, may be seen ruined and over turned here. The anniversary of this futile contest was mentioned in a propaganda station message by Baron Praxis. He afterward acknowledged how it was a very "foolish plan."
Towards the end of Jak II, however, Jak visited the nest and managed to penetrate it using the Precursor Stone to activate Mar's gun ("Break barrier at nest"). The majority of metal heads were deployed in Haven City during the historical Metal Head invasion, rendering the nest's first-response defenses mostly absent. Once inside the nest, Jak managed to defeat Metal Kor, compromising and scattering the metal head forces. With the nest empty, Jak was able to send the Shadow (a younger version of Samos Hagai) and the kid (his younger self) into the past through the rift gate using the rift rider that was transported to the nest.
The nest lies south, south west of Haven's border, among the rest of the hazardous wasteland outside of the city. The initial area of the island surrounding the nest consists of mostly ruins, possibly indicating that the nest was formerly inhabited by a non-metal head species. A robot guard secures the coast of the island. The nest itself is a large mountain, inside of which contains terrain typical of metal head occupation, such as mutated vegetation, petrified structures, and various green and purple-colored bio-mechanical devices. The core of the nest is where Metal Kor can be found, suspended from organic cables over an endless pit. This area also contains the rift gate.