Sers Erryk and Arryk Cargyll were twin brothers and members of the Kingsguard who were split up by the realm.
Ser Erryk helped Rhaenyra escape and left with her to Dragonstone while his brother Arryk stayed behind to serve under King Aegon.
After the death of Prince Jaehaerys, Criston is admonished by Aegon and pushed away by Alicent so he takes out his frustrations on Arryk.
He blames Arryk for not being at his post and protecting the young heir before offering him a chance to redeem himself.
He tells Arryk to go to Dragonstone under the guise of his brother and kills Rhaenyra for ordering Jaehaerys’ death.
Arryk is uncertain of this task but goes along because he doesn’t want to disobey an order from his superior.
A wedge between blood
Arryk travels to Dragonstone and passes through successfully but Mysaria notices his presence and rushes to warn Rhaenyra.
Arryk makes it to Rhaenyra’s chamber but Erryk arrives in time to save her. The two brothers duel each other without holding back.
Blow by blow, the conflict progresses with no one else intervening because they are unable to tell which brother is which.
They brand each other a traitor for picking the other side and continue striking until one of them mortally wounds the other.
He apologizes to his brother before killing him and then turns to Rhaenyra and stabs himself. He refers to her as “My Grace” and apologizes, suggesting that Erryk triumphed.
He couldn’t comprehend living with the guilt of killing his brother and subsequently ended his own life.
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