Canon Background
https://awoiaf.westeros.org/index.php/Royce_Coldwater

In-Campaign
When Maester Thaddeus, Ser Carsen Thorne, and Jardon Pyke called on Coldwater Burn on behalf of House Jasper Royce received them with his maester. He initially rebuffed their requests to take his finest knight, and one of only two knights sworn to Coldwater. However, the trio made a compelling case that Denys was equally needed at Snownook and that he could improve his skills there. When Denys spoke in favor of leaving Royce acquiesced and released him from his oath on the condition that House Jasper aid House Coldwater if called to do so.

When a second delegation from House Jasper, led by Teddy, arrived in July of 284 AC Royce met them along with his wife, Joanna, and Maester Loras. Royce thanked Teddy for returning the ancient bronze knife of House Coldwater, which had been lost when his father fell in the Taking of Gulltown. However, Lord Coldwater became miffed when Teddy attempted to parlay this deed into support for House Jasper. Royce explained that returning a possession to its rightful owner does not grant one favor in his eyes. With his wife’s suggestion, Royce asked that Ser Denys be allowed to return to Coldwater Burn but was rebuffed. Eventually, House Coldwater agreed to support House Jasper as Marshall of the region in exchange for a favor to be named later.

He was present in the Tower of the Hand when Jon Arryn appointed House Jasper as Marshall of the FIngers and the Isles on the day Robert Baratheon wed Cersei Lannister, He wore his recently recovered dagger on his hip and smiled at the appointment. He was accompanied by his wife and infant son.

Teddy revealed to Royce in 285 AC that on his expedition to Valyria House Jasper procured a single dragon’s egg. Royce also inquired if Jon Lynderly had arrived as they are friends from boyhood, he was disappointed to learn that House Lynderly had abstained from the tournament being held at Snownook.