Oswell Whent

Oswell Whent is an unseen character in Game of Thrones. He is not expected to appear in the series, being long dead by the time it starts. Ser Oswell Whent was a knight of House When a sworn brother of the Kingsguard of Aerys II Targaryen.

Season 4
Ser Oswell is mentioned in the entry of his sworn brother, Lord Commander Gerold Hightower. The entry mentions the death of Ser Oswell along with Ser Gerold and Ser Arthur Dayne, fighting a small force led by Eddard Stark in the Red Mountains after refusing to bend the knee to the new king, Robert Baratheon.

In the books
In the A Song of Ice and Fire novels Ser Oswell Whent was a younger brother of Lord Whent, known and remembered for his dark humor. He wore a distinctive helmet emblazoned with a black bat with its wings spread, symbolizing House Whent. Oswell was present at the Tourney at Harrenhal where Jaime Lannister became a Kingsguard.