Fool

The mysterious spirit of the stage. He is invisible to everyone but those who are destined to do great things on the stage and/or whose heart is completely dedicated to the stage. He appears to Sora shortly before she appears on the Kaleido Stage for the first time.

Fool is a pervert who tries many times throughout the series to see Sora, and sometimes her friends, naked. Sora is quick to prevent Fool's advances in any given situation by trapping him somewhere or rebuking him forcefully, most often in a slapstick fashion.

In his more useful moments, he acts as a fortune teller, revealing possible futures to Sora. In the first season he reads the future from tarot cards, and in the second season he reads and reveals the hidden workings of intercharacter relationships via astrology.

Later in the first season, Layla becomes capable of seeing Fool as well; the same happens to Rosetta at the end of the second season, who takes his advice more seriously than Sora, most of the time where Sora can tell he is only doing so to satisfy his perversion.

Fool seems to be the spirit of a real jester who once was devoted to a princess who never smiled.