In the hope of attracting more attention from her sister, Skuld builds Banpei-kun RX. When Mara arrives, Banpei drives her away, thus proving its worth. Unfortunately, Banpei consumes considerable power, thus causing disruption to Keiichi's work and Urd's entertainment. Skuld responds by modifying Banpei to be more power efficient. Things continue to go awry when Banpei attacks Keiichi, believing that it is defending Belldandy. Although it was never programmed to behave in that way, Banpei has modified its own programming because of its love for Belldandy. Banpei constantly follows Belldandy around, learning to accept the others only as a result of Belldandy's teachings and example. When Mara returns, Skuld and Banpei work together to rescue Belldandy's lunch, but Banpei loses its memory and personality when saving Skuld.