From A Wiki of Ice and Fire
Dagmer Cleftjaw by Rafal Hrynkiewicz . © Fantasy Flight Games.
|Title||Captain of Foamdrinker|
|Book(s)|| A Clash of Kings (Appears)|
A Feast for Crows (Mentioned)
A Dance with Dragons (Mentioned)
|Played by||Ralph Ineson|
|TV series||Season 2|
Dagmer has snow white hair and a hideous scar. A longaxe blow had nearly killed him as a child, splintering his jaw, smashing his front teeth and left him four lips instead of two. He wears a shaggy beard, but the hair does not grow where the scar is.
In his youth, Dagmer Cleftjaw was the most dreaded warrior of the Iron Isles. He may have been master-at-arms of Pyke, as he is noted to have trained young Theon in arms. Theon gets on well with the old raider, whom he calls "Uncle" on account of his having a female Greyjoy ancestor four or five generations back.
A Clash of Kings
Lord Balon Greyjoy sends Dagmer to Old Wyk to raise the Stonehouses and the Drumms. After Dagmer is successful raising the houses, he is then ordered to accompany Theon on a raid to harry the Stony Shore. During the raid on the Stony Shore, Theon orders Dagmer to stay behind and defend the ships, which Dagmer laughs at.
When Theon returns from the scene of the massacre, Theon convinces Dagmer to follow his plan to take Winterfell. Dagmer would begin by attacking Torrhen's Square and drawing out the garrison from Winterfell. Then Theon would slip in and take the under-manned castle while the garrison was away.
A Dance with Dragons
Dagmer continues to hold Torrhen's Square with his force of ironborn.