Marlin Dormund

"This letter detailing our infantry movements was meant for Lord Damon of House Marbrand. It was sent to Lord Marlin of House Dormund."

- Tywin Lannister

Damon Marbrand is a northern lord and the head of House Marbrand. He is a bannerman of House Stark.

Season 2
Due to Ser Amory Lorch's nigh-illiteracy, a letter from Tywin Lannister to Lord Damon Marbrand is sent instead to Lord Marlin.

In the books
In the A Song of Ice and Fire novel, there is no mention of any character named Marlin Dormund or House Dormund.