Sunfall is one of the three main cities in Horizon Zero Dawn. It is the capital of the Eclipse and the Shadow Carja. It was once the Mad King Jiran's summer palace until his loyal followers claimed it as their capital.
The city of Sunfall was first established by the seventh Sun-King, Basadid. After his younger brother Iriv, the sixth Sun-King, vanished while exploring beyond the canyons of the Daunt, Basadid declared the west "forbidden" and became increasingly concerned about the potential dangers lying beyond the Sundom's border. He ordered the construction of a large military fortress on the western edge of the Sundom and named it "Sunfall." Despite Basadid's concern about enemies in the west, no great threat emerged and future Sun-Kings paid little mind to Sunfall, instead focusing on the homeland from the Carja capital of Meridian.
The western fortress fell from Carja memory until it was personally inspected by the eleventh Sun-King Marzid during the sixth year of his reign. Marzid was quickly struck with a vision of a grand Citadel in Sunfall and ordered the immediate construction of a large palace in the city. Once the Citadel was complete, Marzid began using it as a summer getaway from the Palace of the Sun. Many nobles of the Sun-Court joined Marzid and over time Sunfall became a bustling artisan city. Large artworks were commissioned and the Sun-Ring, once used for military training, was repurposed as a stage for pageantry and entertainment. Sunfall continued to evolve as the cultural hub of the Carja Sundom until Sun-King Marzid was succeeded by his brother, the twelfth Sun-King Hivas, whose primary focus was military strength.
The Reign of Jiran
During the reign of the Sun-King Jiran, the city was used for military training and eventually became the key location for the Mad King's idea of sport and games. However, the city suffered a major change following the death of Jiran. His remaining loyalists fled Meridian, the latter having fallen to his son Avad. Seeing him as a usurper, the loyalists took prince Itamen and his mother to Sunfall, declaring the boy as the new Sun-King and holding him hostage by the high priests at Sunfall, who declared the loyalists to be Shadow Carja. This soon began a civil war with the Carja of Meridian.
The first section of the city is the slums, where the refugees who fled Meridian reside. With little available space, the people were forced to live in makeshift houses outside the palace itself.
The second and most distinctive feature of the city is the King's palace, a large citadel consisting of balconies and alcoves with a view of the land and the rest of the city. The main room of the palace is the throne room, which is near the center and is distinct in having the Sun-King elevated above the rest of the room, with a commanding view of the arena.
The third and largest area of Sunfall is the arena, where great games were once held. The design was such that prisoners or criminals would be lowered to the arena without weapons and fight to the death against machines for the enjoyment of the crowd and the Sun-King. Helis often did this to remove people who were treasonous to the Shadow Carja.