Theon Greyjoy

Lord Theon Greyjoy, also called Theon the Kinslayer, is a member of House Greyjoy and Lord Paramount of the Iron Islands.

Background
Theon arranges the murder of his father Balon Greyjoy and banishes his sister Asha, therefore inheriting his seat as Lord Paramount but forever being known as "kinslayer".

"A Game of Thrones" (298)
Theon, as ruler of the Iron Islands, wishes to become independent from the Seven Kingdoms.