The Red Raids were a series of attacks conducted by the Carja military under orders from the 13th Carja Sun-King Jiran against other tribes. Units of Carja soldiers invaded foreign territories, such as those of the neighboring Nora and Oseram, and abducted their tribespeople to be used for human sacrifice. It was only when Jiran was overthrown and killed by his son Avad that the raids ended.
In the fifteenth year of Sun-King Jiran's reign, the machines, which had heretofore stayed away from humans, began to become more aggressive toward them, culminating in attacking humans on sight. This became known as the "Derangement" of the machines. Sun-King Jiran believed the Derangement to be a punishment from the Sun, worshiped as a deity in the Carja religion. Already notorious for his harsh treatment of his own people, Jiran decreed that human sacrifice would appease the Sun and ordered the military to raid other tribes for victims.
For years the Carja descended upon other tribes' settlements, rounding up residents for transport to holding facilities, notably the outpost at Daytower, before being sent to the Carja capital Meridian, where they would be sacrificed in the Sun-Ring, killed by machines. The Carja soldiers and their commanders often practiced severe cruelty toward the tribes that they raided; unit commanders such as Zaid and Jiran's champion Helis became legendary for their brutality.
Eventually, even some of the Carja tribespeople were disgusted by the raids. Among them were members of the Carja Hunters Lodge. Led by the hunter Talavad Khane Padish, members of the lodge raised strong objection to Jiran over the raids. However, Jiran had no issue with using dissenters among his people as well as foreign tribespeople for sacrificial victims, and threw the hunters into the Sun-Ring. The fight the hunters put up against the machines became part of the proud history of the Lodge, though it went unrecognized until long after the raids ended.
But the members of the Hunters Lodge were not the only Carja who objected to the raids. Opposition also came from within Jiran's own house. Prince Kadaman, his eldest son and heir demanded an end to the killing. Jiran responded by having him executed.
The night of Kadaman's execution, Jiran's middle son, Avad, realizing that the atrocities would end only with his father's death, fled Carja territory with a garrison of soldiers who opposed the raids. In exile, he formed an alliance with Oseram freebooters and led a successful attack against Meridian. The Carja forces loyal to Jiran fled to Sunfall on Jiran's orders, while Jiran himself stayed behind in Meridian to face Avad. Avad tried to reason with his father, but was forced to kill Jiran when the latter refused to step down. Taking the throne, Avad ended the raids. Furthermore, he sent envoys bearing messages of apology to the tribes that his father had terrorized and expelled soldiers who had participated in the raids from the Carja military.
The Red Raids left an indelible stain on the history of the Carja. Jiran was labeled "the Mad Sun-King", and was despised by almost every tribe (the exception being the Shadow Carja, the Carja splinter tribe formed from his loyalists).
Animosity toward the Carja remained strong for years among the tribes that were raided, particularly among the Nora.
Furthermore, the raids had repercussions that did not occur until years after their end. An Oseram inventor named Dervahl had attempted to lead his people against the Carja in retaliation for the raids while they were happening. In retribution, Jiran had Dervahl's wife and child captured and sacrificed in the Sun-Ring. This caused Dervahl to be consumed with revenge and lose all sense of balanced justice; he craved the death of every Carja, man, woman, and child, and the complete destruction of Meridian. His hatred grew to the point where he even became an enemy of his own people, to the point where they actively searched for him to kill him.
Years after the raids, he attempted to enact a plan to destroy Meridian, but was foiled by Aloy, finally leading to his capture. The Red Raids thus indirectly almost caused the destruction of Meridian and the deaths of many Carja tribespeople who had nothing to do with them; while Dervahl was responsible for his own actions, it was the Red Raids that catalyzed his change into an enemy willing to butcher innocent people to get revenge, an enemy that even his own people wanted dead. Indeed, while speaking to Aloy about him, Avad mused on what great contributions Dervahl might have made using his talent, has it not been for Jiran's cruelty.