0 - The Fool (Callisto)
Callisto in the guise of the fool is Xena's guide in Illusia. She is an odd choice as the character herself has little to do with the Fool. However, as Xena's nemesis has she is a good choice to introduce Xena to the illusionary world. There can also be no doubt at all about Calliasto's character given that her costume is a fabulous reconstruction of the Rider-Waite Fool.
The Fool is the perfect card to begin with, as Illusia is very much a leap into the unknown.
You could argue that her juggling implies the Magician, but I don't think so. The Magician is a master of the elements, and not a performer.