S1·E11 I Opened It...
Aired January 6, 2004
Synopsis
Yuna's father sent Dr. Akai some vials containing potions that might help Kazuki increase his magic count. Yuna ended up inadvertently releasing a pathogen from the vials that takes on her form but completely opposite personality. While Yuna goes around thinking of ways to save Kazuki, Dark Yuna wreaks havoc in the school.