Izuna

She is Thatcher's sister. She and her brother have the duty of protecting the light stone, which was given to their village by a 'legendary hero' with a Pikachu many years ago to operate the mountain's lighthouse. She uses her Magnemite to charge the light stone, allowing passing travelers to make their way safely through the heavy fog. During the episode, she mistakens Ash and his friends as the thieves that stole the light stone (when it was actually Team Rocket), but later apologizes for her mistake. She is also grateful to Ash for teaching her brother how to believe in his Plusle and Minun. Bulbapedia