|Allegiance|| House Cargyll|
|Died||In 129 AC, at Dragonstone|
|Book(s)|| The World of Ice & Fire (mentioned)|
The Rogue Prince (mentioned)
The Princess and the Queen (mentioned)
A Game of Thrones (mentioned)
A Clash of Kings (mentioned)
A Feast for Crows (mentioned)
According to Septon Eustace, Ser Arryk found Prince Daemon Targaryen and Princess Rhaenyra Targaryen in bed together, some half a year after the tourney to celebrate King Viserys' and Queen Alicent's fifth year anniversary, 111 AC. Court jester Mushroom disagrees with this tale.
After the death of Viserys, Arryk sided with King Aegon II Targaryen and the greens. After the coronation of Aegon in the Dragonpit, Arryk led the king into the throne room of the Red Keep. His twin Erryk, however, aligned himself with Queen Rhaenyra Targaryen and the blacks. Arryk and Ser Gwayne Hightower were in the retinue of Grand Maester Orwyle when he traveled from King's Landing to Dragonstone in an unsuccessful attempt to reconcile the rival Targaryens.
Arryk's Lord Commander, Ser Criston, ordered him to infiltrate Dragonstone as Erryk, although it is disputed whether his mission was to kill Rhaenyra or her children. The twins came upon each other in one of the hallways of the castle's citadel and fought to the death, however. According to songs, the brothers professed their love and died in one another's arms after fighting for an hour. Mushroom, however, claims they called each other traitor and were both mortally wounded within moments.