|Name:||Nazo no Cardian|
|Lives:||Inside a card owned by Ail and An|
|Occupation:||Servant to Ail and An|
|First Anime Appearance:||Be Careful After School! Usagi is Targeted|
|First Manga Appearance:||N/A|
|First PGSM Appearance:||N/A|
The Mysterious Cardian was the Cardian that made a brief appearance in episode 57. It was immediately destroyed by the Sailor Senshi at the beginning of the episode, and therefore no information is known about her, not even her name. Even official data only described her as a "mysterious Cardian."
When her card was shown, she was shown with blue skin, orange hair in a style shaped vaguely like a crescent, and wearing a pink outfit with large green shoulder ornaments.