Adonis is the ruler of the Gamma and father of Alia, Adel and Alain. He was thought to be the central antagonist of Kamen Rider Ghost, but the role is being carried by Adel, and much later, the Gammaizers.
Adonis was a close friend of Edith ever since the two were young. He and his wife Alicia had four children, Argos, Alia, Adel and Alain. However, after his wife and his eldest son, Argos, died due to illness, Adonis vowed to create a perfect world, and to that end masterminded the Demia Project to purify the human realm and connect with Gamma World through peaceful way.
Sometimes in the past, his follower Danton use to work for him and Edith on creating the earlier project of Demia and Gammaizers. However, Danton becomes deluded upon realizing the incoming danger of Demia and Gammaizers’ capacities through entire universe and creating an alternate to do humanoid-based experiment on remodeling their people and themselves, but Adonis rejected it, leading a civil war between them, and Danton is latter imprisoned for his crimes.
Adonis was at one point called to a meeting by his friend and magistrate Edith, who asked Adonis to reaffirm his beliefs.
Adonis later had his Eyecon body destroyed by Adel, who framed Alain for their father's death and usurped the throne. However, because only his Eyecon body had been destroyed, Adonis was able to survive in his normal body, though he was trapped within an invisible barrier by Adel.
However, he was discovered by Alia, but Adonis warned her not to come any closer to the barrier as it may hurt her. He also warned her that the Gammaizers were becoming self aware and that they may try to manipulate Adel. This is because Adel though his father never cared his family since the death of his beloved wife and Argos by illness, making Adel being a perfect puppet to Gammaizers.
Adonis was later found and saved by Takeru Tenkuji, who had become allies with his son Alain. Alain and Takeru attempted to escort Adonis out, but Adel's forces showed up to kill Alain, cutting his reunion with his son short. Adonis ultimately sacrifices himself to save his son, telling Alain he loves him and that he believes he will carry out his good will, before Adel finishes him off.