|Alias(es)||Lord Owain the Betrayer|
|Died||In 130 AC, Tumbleton|
|Book(s)||Fire & Blood (mentioned)|
When the host of blacks led by Ser Garibald Grey and Lord Roderick Dustin marched south from the riverlands to Tumbleton, they were joined by men from the Blackwater Rush, including Lord Bourney and Ser Roger Corne. Owain was secretly a supporter of King Aegon II Targaryen, however. When the Two Betrayers began attacking the blacks during the First Battle of Tumbleton, Roger ordered his men to open Tumbleton's gates to the greens, while Owain did the same at the town's castle. Owain killed Ser Merrell the Bold with his spear. Lord Bourney later claimed responsibility for the greens' victory.
The greens' commanders regrouped in Tumbleton and planned what to do next. Owain desired to take command of the host, but he was opposed by Ser Hobert Hightower, Lord Unwin Peake, and Ser Jon Roxton. Unwin eventually stabbed Owain in the eye during a war council.
—Unwin Peake to Owain
- Fire & Blood, The Dying of the Dragons - Rhaenyra Triumphant.