Kotoko
Kotoko (琴子, Kotoko?) is another laptop persocom like Sumomo, but she was custom-built by Yoshiyuki and has much higher specifications than Sumomo. Kotoko originally belonged to Yoshiyuki, but following Chi's kidnapping, Hideki and Shinbo force Yoshiyuki to transfer ownership of Kotoko to Hideki so that her memories of Yoshiyuki kidnapping Chi cannot be erased. Kotoko is far more serious than Sumomo, and thinks that everyone in the Motosuwa household is crazy, Sumomo in particular. Kotoko is programmed to always tell the truth, no matter what, even when it works to her owner's disadvantage.
In the original Japanese version, her seiyuu (Nogami) once worked together with Sumomo's seiyu (Kumai) in Cardcaptor Sakura (another anime adapted from CLAMP's works, as Li Meiling and Li Syaoran respectively). Ironically, in CCS, Syaoran was the more "mature" one of the pair. Incidentally, Kotoko and Li Meiling have similar hairstyles.