The eldest son of the Greyjoy family. After the Greyjoy family was defeated by the Stark family, he was taken away as a hostage by the Stark family. He was raised by the Stark family like their own child.
He betrayed the Stark family at a critical moment and was tortured by the perverted son of Stark's lieutenant into a slave who obeyed unconditionally like a machine.
After seeing Sansa, he regained his sanity, protected Sansa from the crisis, and then defected to Daenerys.