Pokémon X and Y: Valerie

Valerie really won the Pokémon gym lottery for X and Y, because she got to be the fairy-type gym leader in the generation that Game Freak introduced the new element to the meta. Fairy was retroactively applied to several Pokémon, including Mawile and Mr. Mime, both of which are in her party at the Laverre Gym. On top of having a new typing a lot of players weren’t used to by that point, Valerie’s party is made up of Pokémon that players have to recontextualize, unlearning some of what they’d learned from previous games. Mr. Mime and Mawile are suddenly not weak to the same attacks they were a game ago, and they also have new tools to counter Pokémon they would have once cowered from. Want to use a fighting Pokémon to target Mawile’s steel typing? Well, too bad, it’s a steel/fairy-type now, and can wreck your shit. If Mawile and Mr. Mime haven’t rocked your world by the end of the fight, her Sylveon will finish off whoever’s left.
The fairy type was brought about to counter dragon-type Pokémon, but Valerie’s fight is a reminder that the type mows down a whole lot more than just your favorite Dragonite or Salamence.