The Drunkard's Tower is so named because of its great lean. It stands in the bog where the south and west walls once met. The tower is covered in green moss.
A Game of Thrones
A Dance with Dragons
During the siege of Moat Cailin, Ramsay Bolton sends Theon Greyjoy to offer the ironborn garrison of Moat Cailin food and safe passage if they surrender to House Bolton unarmed. Theon passes by the Drunkard's Tower to enter the Gatehouse Tower, where the majority of the garrison are. He discovers eighteen ironmen still hold the Drunkard's Tower.
—thoughts of Catelyn Stark
The Drunkard's Tower leaned as if it were about to collapse, just as it had for half a thousand years.—thoughts of Theon Greyjoy