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Garon is the king of Nohr and is the primary antagonist of Fire Emblem Fates Birthright and Conquest. Originally, he was a stern, but fair man, according to his son Xander, but was then consumed by a great evil who clouded his fair sense. He worships Anankos, and is the father to Xander, Camilla, Leo and Elise.
Garon was formerly a loving father to his children, but was turned evil by Anankos. In Conquest, it is revealed Anankos had replaced him with a literal monster that normally appeared human. Before the events of Fire Emblem Fates, Garon proposed a peace meeting between himself and the king of Hoshido, Sumeragi, who expected to finally stop all conflict between the two kingdoms. Upon arrival with his child, Sumeragi is brutally murdered by Garon's army of archers. Garon then takes the child, and raises them in a secluded fortress.
Before making the choice of which kingdom to join in Fates, Garon sees that after many years of being trapped from the outside world, that his 'adoptive' child is ready to get involved in Nohr's army. Their first task is to kill two prisoners, a task which to Garon sounds easy, but to his child impossible. He finds killing amusing and gets angry at those who don't do it upon request. His biological son Leo steps in and pretends to kill them, satisfying Garon's wants.
Due to them not performing their father's set tasks, the avatar joins Elise in apologising to their father, and they are surprised to be forgiven so easily, but with a catch. To prove their alliance, his adoptive child must go on their first military mission to the outskirts of Nohr, close to Hoshido's borders. He grants them a blade named Ganglari.
He sends the convicted murderer Hans along to help his child, despite his other children's skepticism. Upon arrival to the site, the Nohrians are put before Hoshidan soldiers, who would not harm them unless provoked. The avatar agrees, but Hans does not, and brutally kills one of Hoshido's soldiers. This provokes the Hoshidans which makes them attack, but they are later defeated. Hans is then placed before the avatar's dragon form and explains that he was only following Garon's orders, which shows that he wanted his child to be killed. However, instead of dying, they are kidnapped by an ally of Hoshido, Rinkah.
Garon himself is not seen again until chapter 12, where the avatar reaches Cyrkensia. They plan to kidnap Garon at the opera house Garon is at. Zola, a former underling of Garon's, puts a spell on Azura so she appears to be the famous dancer Layla. Azura's song causes Garon pain due to its nature, and Garon sees through Zola's spell. Zola askes Garon to spare the avatar due to their kindness, but Garon executes him. The avatar's army escapes.
The avatar's group breaks into the castle, defeating Camilla and killing the Nohrian generals Hans and Iago, as well as Xander. When they reach the throne room, Garon taunts them and calls his own children "pawns for the war." The avatar, knowing Garon cannot be reasoned with, attacks, but their sword cannot penetrate his armor. Garon attacks the avatar, Azura, and Ryoma, and tells them to surrender. The avatar's Noble Yato sword is transformed into the Blazing Yato, which can harm Garon. Their armies clash, and Garon is defeated. He refuses to die, using Anankos's power to transform into a dragon. The fight continues, and Azura uses her song to weaken him. He is killed, and hints that he had been long dead, before dissipating into water.