Diantha (Pokémon X and Y)

For the top three, honestly, the data wins out in the best Champion’s placement, because Diantha and our other two remaining trainers have some of the best teams of any trainer in any Pokémon game. The Kalos region Champion’s team is as fierce as it is elegant.
Diantha’s team starts out hitting hard with Hawlucha and stays at that caliber until Mega Gardevoir takes the stage at the very end. Her team broadly has an Achilles’ heel in the fairy type, which was new to Pokémon X and Y, so it makes some sense that she would encourage players to take advantage of this new addition to the meta. But as TikTok’s @amarcheo points out, across Diantha’s team of six, she’s the only one who has a super-effective move against every Pokémon in the Pokédex.
Diantha is underrated as hell.