Adonis (アドニス Adonisu) is the emperor of the Gamma and the father of Alain, Adel, Alia, and Argos. He is a reasonable emperor who cares for his people and family. After the deaths of his wife Alicia (アリシア Arishia), firstborn child Argos and many of his comrades, he falls into despair and plans to create the Demia Project to ensure immortality for the Gamma. Due to this, he was chosen by the Great Eye and uses its power to realize Edith's machinations, which transfers the souls of the Gamma World population to Eyecons but the immortality he sought is rather far from what he intended, as his citizens dying from the machine. He reluctantly approved the invasion of the human world to solve this problem, which was the idea from Igor and his son, Adel.

Adonis soon started to genuinely regret for taking the lives of innocents, causing him to doubt his actions but Adel quickly killed him by deeming his father as imperfect due to said act. Although his Gamma Eyecon body was destroyed and he returned to his human body, he remains imprisoned by Adel, all while his son Alain is framed for the crime which Adel committed. With the arrival of his son, Alain, and his newfound ally, Takeru Tenkūji, Adonis is rescued by Takeru and is reunited with Alain to start their new ways in creating a true perfect world with Takeru's help. However, the reunion is cut short when Adel's army attempts to kill Alain. Adonis sacrifice himself to save his son, leading Takeru to avenge him against Adel's army. While dying in Alain's hands, Adonis tells him that he loves him and to listen to what his heart says, not wanting his children to follow the same mistake he did shortly before his elder son, Adel destroys him in front of both Takeru and Alain. Before his death, he already prepared to prevent his children into contacting Great Eye, most of all to prevent his second son, Adel from doing so, as his wish may endangered both two worlds, and he himself is too weak to be manipulated by the Gammisers' manipulation.

Adonis is portrayed by Hiroshi Katsuno (勝野 洋 Katsuno Hiroshi).

Series:  Kamen Rider Ghost