Student number: 1

The helpless and meek ghost of a former student, Sayo Aisaka has low self-esteem and is not skilled at being a ghost, tripping even though she doesn't have feet and being completely unable to scare people, more often frightening herself than others.

She is invisible to almost everyone, and her presence goes mostly unnoticed though Takahata had her included in the class registry, with a note to Negi not to change her seating.

Sayo has been friendless and lonely for around 60 years since her death, which made her very desperate for a friend, and later attempts to talk to the rest of the class during the preparations for the School Festival.