Daigo Fukami (深海 大悟 Fukami Daigo) is the long-lost father of Makoto and Kanon who abandoned his children without telling them his reasons for this, and then suddenly disappeared without a trace in his children's childhood life after the death of his wife. His disappearance has made his children worried sick for waiting his return too long. While Makoto developed a hatred towards his father because of this, Kanon believes there must have been a good reason for why he left them. As it turns out, his long disappearance was the result of him getting killed by a sword wielding Gamma Ultima. However, he managed to resurface as a ghost along with the Gamma's first prince, Argos. He can transform into the original Kamen Rider Specter known as Kamen Rider Zero Specter (仮面ライダーゼロスペクター Kamen Raidā Zero Supekutā). Upon Argos' recent downfall of betraying both Daigo and Edith, the former is currently on a mission to stop Argos from awakening an entity known as Kamen Rider Extremer. Once he arrived in the world Argos created, Daigo expected his son to come after him for what happened in their past. He originally had the Darwin Eyecon with him until Dark Ghost interrupted his battle against his son and took it from him. He reconcile with his son, once he explain his reason why he left his children to Daitenkū-ji since his wife died, unable to return to his children for his important duty to save the world from evil, and observes what Argos has been planning, even after his human body is killed by a sword wielding Gamma Ultima.
Daigo Fukami is portrayed by Ikki Sawamura (沢村 一樹 Sawamura Ikki).