Dagmer Cleftjaw is a character from A Song of Ice and Fire and its TV adaptation Game of Thrones. In the TV series he's played by Ralph Ineson, who also portrayed Amycus Carrow. He is ironborn captain the Foamdrinker, while in the HBO tv series he's the first mate of the Sea Bitch. He takes orders from Balon Greyjoy and helps Theon Greyjoy on a raid to harry the Stony Shore then later to take Torrhen's Square and Winterfell along with his men. In the TV series Dagmer and Theon don't seem to know each other before the second season.