From Bulbapedia, the community-driven Pokémon encyclopedia.
Sheila (Japanese: シマ Shima) is a recurring character in the Pokémon anime. She is long-time friend of Mahogany Town Gym Leader Pryce and serves as the official referee at the Mahogany Gym.
Ash and his friends first met Sheila in As Cold as Pryce. She learned that Ash was after a Gym battle against Pryce, so she took the group over to his meditation spot in the mountains. After Ash and Pryce fell into a crevasse because of Team Rocket, Sheila led Brock and Misty down the steep canyon walls. During the search effort, she revealed that Pryce was once a spirited Trainer before becoming his now cold self after his partner Piloswine disappeared one night. Pryce and Ash later emerged from a cave, and Sheila was surprised to see Piloswine once again.
In Nice Pryce, Baby!, Sheila was glad to see her old friend Pryce back to his much friendlier self. She later refereed Ash's match against Pryce.
Sheila is a remarkably adventurous individual, with an equally interesting past that was only hinted at when she revealed her status as a Triple A accredited judge. Her energetic spirit surprised Ash and his friends when they first met her. She is unpredictable and always one step ahead of everyone else.