Ando included references to Greek mythology in Zodiac P.I. in the names of the astral spirits. The astral spirit of Virgo, Demeter, takes her name from the goddess of the harvest, while the astral spirit for Capricorn, Parn, is a reference to the god Pan. Astrea, the astral spirit for Libra, is named after the goddess of justice. The twin astral spirits for Gemini take their names from twin brothers Castor and Pollux. The centaur Chiron is alluded to in the name of the astral spirit for Sagittarius. The name of astral spirit for Taurus is a reference to the woman Io. The astral spirit for Pisces and the spirit for Aquarius take their names from the goddess of love and Ganymede, respectively. Other references include stars. Ando named Antares, the astral spirit of Scorpio, and