Thunderjaws are an iconic machine in Horizon Zero Dawn having appeared in various marketing campaigns leading up to the game’s release. There are few moments as epic as fighting your first Thunderjaw in the game and you will never feel more powerful than when you're watching your enemies try in vain to take down a Thunderjaw you’ve overridden.
These mighty behemoths play an important role in the game’s lore and many players are unaware of some of the more interesting facts regarding these apex predators.
After seeing the threat tribal hunters posed to the machines’ operations, the artificial intelligence Hephaestus created Thunderjaws to respond to those threats. These gargantuan machines were built solely for war against large numbers using heavy armor, devastating weaponry, and single-minded aggression.
Prior to the events in the game, these machines were largely successful in attacking tribes, killing hunters, and other violent acts against humans. It’s unclear if it was because of this success that only a few were ever made or if the resource requirements were too large to justify building more than a handful.
Of all the machines present in the game the Thunderjaw was the first one to be implemented by the game’s designers. It seems fitting that one of the fiercest and largest machines in the entire game is the one the designers first focused on.
The technological feats of this machine are impressive as it boasts 271 animations, dozens of destructible armor plates and 12 unique attacks. It’s also said to have taken around a year and a half before the monster was ready for the game.
Thunderjaws have the unique distinction of being the most feared machine among all of the tribes. These brutes have been known to tear apart entire villages, slaughter groups of hunters, and their very movement can destroy forests and cause small earthquakes.
Even the expert hunters of the Hunters Lodge are cautious to take on these beasts and many aspiring members have fallen beneath the metallic claws of a Thunderjaw. Before Aloy came along, Thunderjaw kills were considered rare and anyone who managed to kill a Thunderjaw was considered a legendary hunter.
With the legendary status surrounding these machines, it’s interesting to note that, apart from Tallnecks, it’s the most commonly encountered large machine found in the game. There are six sites that Thunderjaws can be found at with about five units found outside of these locations.
Other massive machines like the Rockbreaker or the Stormbird have fewer machine sites and fewer isolated encounters. It’s unclear why Thunderjaws are so much more prevalent, but it makes annihilating their entire population that much more impressive and gives plenty of opportunities for the player to obtain the valuable drops that come from Thunderjaws.
As if hinting at the important role Aloy would play in the world’s future, the first time Thunderjaws were ever seen by the people in the game was the same day of Aloy’s naming ritual. Rost was carrying the infant Aloy home when two Thunderjaws were spotted in the Sacred Lands in a large field.
The presence of these previously unseen beasts was a foreshadow of things to come. These Thunderjaws would go on to terrorize all of the tribes and lead to countless deaths. But the lands would be liberated by that same infant whose naming day was forever memorialized by the first sighting of these terrifying foes.
It’s unclear what happened to the two Thunderjaws that appeared on Aloy’s naming day, but it’s likely the Nora Braves acted swiftly to take them down before they caused too much damage. Of all the tribes, the Nora seem uniquely capable of preventing machine incursions in the Sacred Lands as Thunderjaws were not seen in the area until the Eclipse brought one to attack the mountain.
It’s possible the Thunderjaws were more preoccupied with taking out the more enterprising tribes like the Carja and took less of an interest in the Nora. Or it could be the geography of the mountains made attacks difficult and they chose to target less naturally defended areas.
The first Thunderjaw that was ever killed was taken down by a hunter named Ahsis. Ahsis was a Hawk level member of the Hunters Lodge when a Thunderjaw destroyed Morning Light, convincing Ahsis to hunt it down. After realizing his weapons weren’t doing enough damage he managed to knock off one of the Disc Launchers and used that to finally bring the beast down.
This act propelled him to the rank of Sunhawk as the Thunderjaw was the deadliest machine at the time and according to the laws of the Hunters Lodge that made him the greatest hunter and defacto ruler of the Lodge.
The strange Banuk Shaman Brin commissions Aloy to kill a Thunderjaw and bring back the mech fluid. This act of drinking ‘machine blood’ caused him to be exiled from his tribe, but yielded an interesting supernatural ability, at least according to Brin.
Supposedly, the consumption of mech fluid grants the imbiber visions of the future. The visions are vague and considered to be a farce until Aloy discovers there is some accuracy to the supposed visions. For instance, when Brin drinks the fluid of a Thunderjaw he reveals that Thunderjaws were a recent creation meant to hunt humans, which he could not have known on his own.
The iconic appearance of the Thunderjaw is unsurprisingly based on dinosaurs, specifically Theropods like the T-Rex or Carnotaurus. Theropods are dinosaurs that are biped and have small limbs to assist in grappling prey.
What’s interesting about the Thunderjaw is that it does not possess forearms like a Carnotaurus. Considering its prey is small humans that would be impossible to grab with small arms the A.I. likely thought they would be a waste of resources and omitted them from the final design.
While there are machine classes in Horizon Zero Dawn that are considered unique, the Thunderjaw is the only one to have a unique machine with a name. This unique machine is called the Redmaw and plays a central role in the quests related to the Hunters Lodge.
Redmaw is a legendary Thunderjaw who has killed numerous hunters and presents the only machine that could dispose of Ahsis from his rule if another hunter killed it. In fact, Redmaw manages to kill Ahsis before Aloy and Talanah bring it down resulting in Talanah’s succession as the new leader of the Lodge.