Hiromu Shinbo
Shinbo quickly becomes Hideki's best friend once Hideki moves into the same apartment complex as him. He is quite knowledgeable when it comes to Persocoms, which ends up in Hideki turning to him whenever he needs help with Chii. He has his own Persocom named Sumomo (Plum). He also attends to the same cram school as Hideki, and ends up being involved with his teacher, Takako Shimizu, when he finds her in a park after being locked out by her husband, who was too involved with his own Persocom.