Melissa

Despite the group having traveled through Hearthome City twice, once in "Dawn's Early Night" and a second time in "Arriving in Style!" the Hearthome Gym remained closed with the Gym Leader nowhere in sight. Melissa (Fantina) had left a note saying that she was going on a journey for a while and to not look for her. Apparently, she was developing a whole new battle style.

She finally appeared in "Playing The Leveling Field!" where she battled Ash and Zoey. She had a tendency to break into dance regularly, occasionally interspersing French phrases in as well, such as "s'il vous plaît." It was also revealed that she battled Alan twice with him winning the second time. It was revealed in "Aiding the Enemy" that Paul also managed to defeat her.

Ash met with Fantina upon returning to Hearthome City in "Barry's Busting Out All Over!" and battled her again in "Shield with a Twist!" where he defeated her and earned the Relic Badge.

In "Gotta Get a Gible!" it was revealed that Melissa (Fantina) has once again left her Gym, so Barry had to take a number in order to battle her when she came back.

Melissa (Fantina) appeared from DP174 to DP177 as a guest judge for the Grand Festival.

(Source: Bulbapedia, edited)