When the King was younger, he found the Wyrdkey hidden in Elena's tomb and brought it to Morath. Duke Perrington then took the King under the Keep to show him the crypt, even though it was forbidden. But the King opened it with the Wyrdkey and Erawan was released; he took over Perrington’s body, and let his minion take over the King's body. Erawan also completely wiped away any memory of the King's name.
The Fall of Terrasen
When Aelin was a child, the King visited Terrasen shortly before the takeover of the country. During a feast in honor of his visit, the King—or the human inside him—tried to influence Aelin to use her fire and kill him, and the Valg living in him.
Shortly before his Conquest of Terrasen, the King of Adarlan issued a proclamation claiming that magic was an affront to the Goddess and her gods as it tried to imitate their divine power. As a result, he outlawed magic and led the purge of magic from Erilea, burning ancient books, sacred sites, and even magic practitioners themselves.
It is later revealed that the Valg planned to use the magic-wielders to conquer Erilea, and he had to make the horrible decision to have them all killed rather than used as vessels against him.
The human still inside the King was scared of what would happen when the Valg discovered Dorian's powerful magic, so he built the Wyrdstone Towers, presumably against the will of the Valg, to rid the continent of magic, however, using his own blood in the spell made his line immune and eventually, Dorian's magic came out.
The King of Adarlan hosts a Tournament in order to appoint a King's Champion, who would perform his dirty work, inviting twenty-three of his council members to each sponsor a would-be Champion.
The King continues his mission to conquer Erilea.
The King orders Celaena to assassinate Galan Ashryver, and sends her accross the sea to Wendlyn. He later has Sorscha, one of the servants working for the Rebels, executed, and possesses Dorian by forcing him into a Wyrdstone collar. The human in him tries to stop that from happening, but ultimately fails to overcome the Valg's possession and can only watch while his son is enslaved.
Aelin and Dorian fight aganist the King, resulting in the Valg controlling him being destroyed. This allows the King to speak freely and he explains to Aelin and Dorian that the Valg forced him to destroy Terassen as the royal family was a threat, being descendants of Brannon. He also reveals that the decree to outlaw magic was done as a way for him to deny the Valg hosts, as they preferred magic users. The King then states that he did it to protect them. Dorian, unable to believe his father, goes into a rage and kills him as he shatters the Glass Palace.
Aelin and Dorian enter a realm beyond time and space, in an attempt to forge the Lock without either of them having to sacrifice themselves. However, the effort that it requires to do so is far too great, and they fail to finish the whole Lock.
Almost defeated, Aelin prepares to push Dorian back into Erilea and sacrifice herself. However, the King reappears from the Afterworld and offers some of his power to help Aelin forge the Lock; because Erawan took his name away, he is essentially "Nameless" as well. Dorian realizes the King is very much human again and realizes he has some kindness left in him. The three together begin to forge the Lock, but Aelin sends Dorian back to Erilea, as she does not want him to die. Aelin and the King manage to forge the Lock, and the King dissipates in the process, giving all he has to forge the Lock. Aelin manages to send the gods back to their world, and as an act of defiance for the gods destroying Elena's soul, opens a portal in the gods world leading to the Valg's hellish dimension and seals the portals forever.
Later, as Dorian and Yrene Towers confront Erawan himself, Erawan reveals the King only remembered his name once more when his first child was born, and named his firstborn son after himself: Dorian.
When the King was younger, and before he had been taken over by the Valg, he was much like his son Dorian, always poking around in forgotten places where he wasn’t wanted and reading books no one his age should read. However, he was inhabited by the Valg when he was still young, which changed him, making him tyrannical and sociopathic.
Under the Valg’s control, the King became a ruler who enjoyed exerting his will over others. He did not appear to care about anything other than himself and gaining more power.
Had he never been possessed, he would have been a loving and kind father, which he showed to his son in Kingdom of Ash.
He was also mentally strong for surviving Valg possession for decades; it is mentioned that common people could only take a few months of possession before they broke. The King also seemed to be able to partially resist the control of the Valg; for example, he built the Wyrdstone Towers. Most people were not able to resist the Valg.
The King was described as not looking at all like his son Dorian; he had a broad frame with a round face, craggy features, and sharp eyes. One of his brows is scarred.
If someone told you that your grandmother was secretly good, that she hadn't wanted to murder your parents and so many others, that she'd been forced to make you kill your own sister, would you find it so easy to believe? To forgive her?Dorian to Manon Blackbeak, Kingdom of Ash
The King's relationship with his son when Dorian was young was never revealed. Around the time that Throne of Glass started, however, it can be inferred that Dorian hated his father, if not for his personality, then for the way that he relentlessly pursued his ambition to conquer all of Erilea. When presented with the option of choosing a Champion for his father's contest, Dorian chose Celaena Sardothien, the most infamous sixteen-year-old in all of Erilea.
In Heir of Fire, when Dorian took an interest in a young healer, he knew his father would not approve and decided to keep it a secret from him. At the end of the book, the Valg possessing the King beheaded the healer, Sorscha, which strained their relationship further.
Throughout most of Queen of Shadows, Dorian was possessed by Valg and didn't express much of anything until the end, when it was revealed that the King was possessed, but Dorian chose not to forgive his father and ultimately ended him.
Empire of Storms and Kingdom of Ash both show Dorian with mixed emotions after his father's death, both with regret and anger over his father, but when Dorian sees his father from the Afterworld, his father shows love and compassion for his son. Dorian seems to show gratitude for what his father offers and lets go of some of his hate.
Later, it's revealed that Erawan wiped away any trace of the King's name, and the King himself only remembered it once: when Dorian was born. The King named his firstborn son after himself.
- Throne of Glass: Chapter 5, pg.