Sumomo
Sumomo (すもも, Sumomo?) (Plum in the Tokyopop translation of the manga), whose name means "plum" in Japanese, is a miniature "mobile persocom" – the equivalent of a laptop computer. Wearing an outfit that makes her resemble a genie, she is programmed to be cute and tends to be quite hyperactive, for example leading Hideki in wakeup exercises each morning and dancing when she is standby mode. Shinbo was the original owner of Sumomo, but left her with Hideki after leaving with Takako. He later transfers Sumomo's registration to Hideki, giving him permanent ownership. At the beginning of the series, Shinbo uses Sumomo in an attempt to analyze Chi, and Sumomo is nearly broken in the process, requiring new main memory, and in the manga, a new video card as well. Once Kotoko joined Hideki, she quickly came to the conclusion that Sumomo was mad, with her nonsensical ways.
In the original Japanese version, her seiyuu (Kumai) once worked together with Kotoko's seiyu (Nogami) in Cardcaptor Sakura (another anime adapted from CLAMP's works, as Li Syaoran and Li Meiling respectively). Ironically, in CCS, Syaoran was the more "mature" one of the pair.