Mirror Serena showed up in The Cave of Mirrors! as a one-off character, basically Serena's evil mirror universe counterpart. While the regular Serena's laid-back and easygoing, Mirror Serena is the complete opposite—arrogant, competitive, and dead serious about Pokémon battles. In the Japanese version, she even speaks in a Kansai dialect to really drive home how different she is from her counterpart.
Content compiled by AnimeList.moe from publicly available sources.
