Fool

馬鹿

Fool is the enigmatic spirit of the stage. He is roughly the size of an action figure and resembles a jester or clown. He appears to Sora shortly before her debut on the Kaleido Stage. Fool is invisible to everyone except those destined for greatness on the stage and/or whose hearts are wholly devoted to it. He appears to be the spirit of a genuine jester who once served a princess who never smiled.
Despite being a spirit, Fool is a pervert who repeatedly attempts throughout the series to see Sora, and occasionally her friends, naked (typically by suggesting they take a shower). Sora quickly stops Fool from peeking in any situation by trapping him or rebuking him forcefully, usually in a comedic, slapstick manner. Later in the first season, Layla gains the ability to see Fool as well; the same occurs with Rosetta at the end of the second season, who takes his advice more seriously than Sora, mostly in instances where Sora can tell he is acting solely to satisfy his perversion.
During his more useful moments, he acts as a fortune teller, revealing potential futures to Sora (in the first season, he reads the future from tarot cards; in the second season, he reads and reveals the hidden dynamics of intercharacter relationships via astrology). He is also the one who explains the inner mechanics of the Mystical Act to Layla and Sora in episode 25, An Amazing Bond.