Stalker

The Stalker is a machine in North and South America. It is a medium-sized Combat Class machine; however it is unique among combat machines in that, while all other known combat machines employ open aggression, the Stalker employs stealth. Its adeptness at ambushing, coupled with its deployment in areas where visibility is challenging, such as jungle environments, makes the Stalker a particularly grave threat to any human in these environments.

Utility

A Stalker’s adeptness at stealth and ambush make it lethal to anyone unfamiliar with its abilities. Foremost among these abilities is its cloaking ability. A Stalker’s stealth generator cloaks the Stalker from plain sight when engaged by bending light around its chassis. In the case of Focus users such as Aloy, it also cloaks the machine from scans. However the cloak is imperfect; through the Stalker cannot be seen, the cloak produces a shimmering refractory effect in the shape of the Stalker’s chassis that is visible to sharp eyes; this is the shimmer that Ghalidid saw. Additionally, it does not cloak the Stalker’s optical sensors, nor mask the distinct whooshing sound of it’s servomotors.
The Stalker’s most lethal weapon is its dart gun, which can kill a human with one shot. Even though the Stalker must momentarily de-cloak to use it, an unsuspecting human never sees the shot coming, since the Stalker fires it from long range. At closer ranges, a Stalker deploys proximity mines that damage and distract an enemy. Unlike the dart gun, a Stalker can deploy these mines while cloaked. It drops these mines as it swiftly changes its position, its cloak preventing it from being tracked. Stalker mines can be detonated by shooting them, and will typically insta-kill Stalkers with 3-4 mines. Though built for stealth and ambush, Stalkers are capable of formidable melee attacks, slashing with their claws and employing a swift bludgeon attack with their tails.

Complexity

The chassis of a Stalker is distinct from that of the other known combat machines in two respects. Firstly, whereas these machines are heavyset and built for power, Stalkers are slender and streamlined. Secondly, whereas the armor of these machines consists of large, white fitted pieces, a Stalker's armor plating is black, and is composed of relatively small hexagonal plates that fit together in a chainmail pattern. Four optical sensor arrays are located on each side of their head, with the sensors arranged in a trapezoidal configuration. Each of their four feet is equipped with three claws. A dart gun is located between its shoulders, and on each hip is a proximity mine launcher. A power cell rests atop its lower back, to which four long, antenna-like structures are attached. The machine has a retractable tail that is almost twice as long as its body, equipped with a sharp spike at the tip. Finally, a cloaking device called a Stealth Generator is mounted on the belly.
Stalkers can be found on their own or in small packs. Built specifically for ambush attacks, the majority of them are deployed in jungle regions, such as The Jewel or the Raintrace, where the dense foliage limits their visibility to humans. They usually position themselves cloaked with heads downward on vertical surfaces such as trees and cliffsides, in absolute stillness. Alternatively, they also walk about uncloaked, partially obscured by the jungle’s undergrowth. In either case, Stalkers place glowing red alarm flares that, when activated by getting too close, will launch into the sky and emit a loud noise. These alarms are not triggered by anything smaller than a human, or by other machines. Upon the triggering of an alarm, all Stalkers in the site will cloak and converge at the area the flare was launched. However, this can be abused by using Tripcasters to set traps and lure the Stalkers into them.
Stalkers are more vulnerable to Shock attacks than other machines. Repeated attacks with weapons that deal Shock damage will quickly stun a Stalker. This vulnerability is absent in Daemonic Stalkers; indeed, like all Daemonic Machines, they are highly Shock-resistant. Also, their head is a known weak point. A triple-arrow shot from a strong enough power bow into the head can destroy one in a single shot.

Discovery

Unlike the Zero Dawn terraforming machines, which were designed and controlled by Zero Dawn’s governing AI GAIA, the Stalker was designed by the AI HEPHAESTUS, which had previously manufactured the machines under GAIA’s direction. When GAIA self-destructed, HEPHAESTUS became hostile toward humans for their predations on the terraforming machines for parts and resources. This began the phenomenon that the tribes call the Derangement. In an escalation of the phenomenon, HEPHAESTUS began producing combat machines, including Stalkers; it apparently created Stalkers from an unknown pre-Derangement Stalker-like machine.