From A Wiki of Ice and Fire
|Book(s)|| A Storm of Swords (appears)|
A Feast for Crows (mentioned)
Dickon Manwoody is the son of the Lord of Kingsgrave.
Dickon, accompanied by his brother, Mors, his father Lord Dagos and his uncle Ser Myles, were part of the entourage of Prince Oberyn Martell when he came to King's Landing to claim the seat Tyrion Lannister had offered Prince Doran Martell.