Philip was an affectionate child, a trait he maintained until his memory loss. However, after his genius was discovered, his isolation from society further damaged his empathy, and he gradually became cold. He began to rely solely on logic to cope with situations. This personality remains even after his rescue, though he is slightly less cold than before. As a result, Philip is generally oblivious and sometimes displays an unnecessarily cruel attitude. A mysterious, sharp, and aggressive amnesiac boy who lacks humanity due to being a test subject. His initial personality is like a prickly cat, having just been rescued after a long period of abuse.

Ryu Terui's wife and Shotaro's reliable colleague. She has a bright and sensible personality. Initially, she clashes with Philip frequently because he finds her too cheerful.

Akiko's husband. He was initially cold due to his quest for revenge for his parents and family, but his heart has softened considerably. He loathes criminal cases, especially those involving abuse.