From Bulbapedia, the community-driven Pokémon encyclopedia.
Sheila (Japanese: シマ Shima) is a recurring character in the Pokémon anime. She appeared in As Cold as Pryce and Nice Pryce, Baby!.
Sheila lives in Mahogany Town, and she helps her friend Pryce out with the Gym. She appears to have known Pryce for a very long time, as she knows a lot about him and seems to be the only person who can understand him. Further, in the dub, she made an indication that she knew Pryce's Piloswine before it was frozen.
Sheila also appears to be a fan of the outdoors and adventure. After Pryce and Ash fell down into a canyon thanks to Team Rocket, Sheila, along with Misty and Brock, climbed down into it to look for him. And when Ash told her he was looking for Pryce, she told Ash to follow her. Shortly afterwards, Sheila was far ahead of Ash and the others. This left her wondering why they were so slow.
In addition to being a friend of Pryce's, Sheila is also the official referee for the Mahogany Gym matches. In the games only, Sheila is Pryce's wife.