Thunderjaw

The Thunderjaw is a machine in North and South America. It is a large Combat Class machine, one of the two largest machines of this class (the other machine being the Tremortusk). Its size, power, and array of heavily damaging weapons make it one of the most feared of all machines. An apex combat machine, equipped with a wide array of heavy artillery and melee attacks.

Utility

Like most large machines, Thunderjaws are found alone. A pair can be found together protecting a herd of Lancehorns in the Glarebreak, west of Free Heap.
The Thunderjaw’s huge size, power, array of weapons, and capacity to sustain damage make it one of the most formidable machines. It employs a variety of powerful melee and ranged attacks.
Additionally, its radar scanner allows quick detection of hunters hiding in tall grass. Unlike that of a Scrapper, which is able to detect only movement, the Thunderjaw’s radar can detect humans regardless of their motion. In Horizon Zero Dawn, Thunderjaws have no elemental weaknesses, and are resistant to Shock. In Horizon Forbidden West, both Thunderjaw variants are resistant to Shock and Frost damage, with the Apex variant having resistances to every element but Acid.
While it is unconfirmed, Thunderjaws can supposedly hear a bow shot. While most machines would investigate where the shot landed, a Thunderjaw will investigate where the shot originated from.

Complexity

The Thunderjaw is a huge bipedal machine with features akin to those of a Tyrannosaurus Rex: powerful and bulky legs, a long body, and a heavy tail to maintain equilibrium. Its body features symmetrical weaponry: a laser weapon in its mouth, cannons on its jaws, a radar array on its back, and Disc Launchers on its hips.
A Thunderjaw's major structural weaknesses are its heart and data nexus; ranged weapon strikes on either cause significant damage once they are exposed. Similarly, landing a shot of the corresponding element on exposed elemental canisters will induce their status effects. Its mandibular cannons, disc launchers, tail and radar unit can all be removed with enough Tear damage, disabling their corresponding abilities entirely.

Discovery

Unlike the Zero Dawn terraforming machines, which were designed and controlled by GAIA, the Thunderjaw was designed by the AI HEPHAESTUS, which had seized control of the Cauldron facilities and begun aggressive countermeasures to the human practice of machine hunting. Thunderjaws are one of the most extreme examples of HEPHAESTUS' escalating attempts to cull the human population, a phenomenon known to the tribes as the Derangement.