Avad is the second-born son of Sun-King Jiran, following Jiran's eldest son Kadaman. During the Red Raids, Avad was wary of his father's commitment to human sacrifices. He became interested in a prisoner taken during the Red Raids, a fierce Oseram woman named Ersa who had made a palace slave after surviving in the Sun-Ring. Avad befriended Ersa, eventually helping her to escape.
Avad's shaky relationship with his father erupted in bloodshed in 3038, when his older brother and the favored heir to Jiran's throne, Kadaman, was executed by his own father for demanding an end to the Red Raids. Finally realizing his father needed to be stopped, Avad and his loyal soldiers fled from Meridian and traveled to the Claim in search of strong Oseram allies. Avad reunited with Ersa, and with her help managed to form a warband of Oseram Freebooters willing to fight to overthrow Jiran.
Avad planned to avoid a drawn-out war between the Carja and Oseram by using his status as the rightful heir to the throne of the Sun to inspire his people, usually wary of tribal outsiders, to rebel against the Mad King and rally behind the Oseram allies.
The Liberation of Meridian
After months of preparation, Avad and his allies marched on Meridian. In an effort to limit the damage to the city, Avad had some of his forces infiltrate Meridian while destroying the outer walls and city gates with cannon fire. Avad's plan worked, as Jiran's forces were thrown into chaos and Avad managed to capture the city. Avad then personally confronted his father and tried to convince him to surrender peacefully. Jiran refused and Avad reluctantly slew him. This made Avad the 14th Sun-King, and the first to ascend the throne through an act of patricide.
After becoming the 14th Sun-King, Avad began a program of extensive reforms throughout the Sundom. He abolished slavery, ended the human sacrifice to the Sun, mandated the elimination of gender and tribal discrimination in the Hunters Lodge, and opened Meridian to foreigners. He also made the Oseram Freebooters from his rebellion into his personal Vanguard, with Ersa as their Captain.
Avad and Ersa also began an affair, which they both kept secret, since Avad feared that the Carja nobility (who were very reticent to accept his end to tribal discrimination) would rebel if it became public knowledge that the Sun-King was involved with an Oseram woman, nor would the Oseram accept the relationship.
Carja Civil War
The Liberation marked the beginning of the Carja Civil War: Jiran's supporters retreated to Sunfall, deeming themselves the Carja in Shadow. The Carja in Shadow (or the Shadow Carja, as other tribes came to call them) refused to serve Avad, labelling him a tyrant for murdering Jiran and deeming Itamen, Avad's younger brother, as Jiran's true successor. After becoming stuck in stalemate, the two tribes agreed to a ceasefire. In the meantime, Avad sent agents into Sunfall to smuggle Itamen back to Meridian, knowing that doing so would revoke the Shadow Carja's legitimacy.
Two years into his reign, Avad sent a convoy to the Nora tribe as a gesture of peace. Soon after, Ersa was found dead at Red Ridge Pass, apparently murdered by the Shadow Carja. In response, Meridian was closed off to outsiders, and Ersa's brother Erend was appointed Captain of the Vanguard. Upon discovering that Ersa's death had been faked, Avad was introduced to Aloy, a Seeker from the Nora who had come to Meridian investigating a recent attack on her own people. After coming to the conclusion that an Oseram named Dervahl was behind Ersa's kidnapping, Avad asked for Aloy's help to deal with the threat. Upon learning that Ersa had died in captivity, Avad was saddened by the news, and asked for Aloy's help in finding Dervahl fast. As Aloy and Erend searched the city, however, Dervahl and his men infiltrated the palace and incapacitated Avad with the same sonic weapon used on Ersa. Before Dervahl could destroy Meridian and force Avad to watch, Aloy arrived and foiled his plans. With Dervahl in custody, Avad thanked Aloy for her help and offered her a place at his side, but she declined, sensing that the offer was a veiled attempt to replace Ersa.
After Aloy and Vanasha successfully helped Itamen and Nasadi escape from Sunfall, Avad happily welcomed them home on the docks at Brightwater. Upon seeing Aloy, Avad thanked her for helping his family return.
Battle for the Spire
Sometime later, Avad was approached again by Aloy, warning him of an upcoming attack by the Eclipse. While Avad insisted that Meridian remain his priority, he agreed to send the Vanguard to the Alight in order to protect the Spire. He ordered the fortification of Meridian's western ridge to protect both the village and the path to Spire. After apologizing for his earlier proposition, Avad asked Aloy to share what she knew about the upcoming attack. Avad ordered the defense of Meridian, and successfully repelled the assault on the city with Aloy's help.
Despite his grand goals and achievements, Avad is a somewhat meek man, responding shyly to praise and seeking to find compromises that benefit as many people as possible in order to avoid making enemies. He also seems to be attracted to strong, dominant women, as evidenced by his relationship with Ersa, as well as his attraction to Aloy (although he claims that the latter was due to emotional confusion following Ersa's death).
Despite Avad's grand ambitions, he understands that "change won't come in a single sunrise", and that fulfilling his goals will take time.