Edith (イーディス Īdisu) is magistrate of the Gamma World and Adonis' closest ally, having propose a machine that can grant immortality to their people by transferring their souls into Eyecons. Though his machine was completed by Adonis using the Great Eye's power, Edith is shocked to find that it only stagnated his people and slowly killed them. As this forced Adonis to order an invasion on the human world to empower the containment machine, Edith attempted to contact the Great Eye but is blocked by the Gammaisers that he created to protect the entity. A decade prior to the series, after being defeated by Ryū Tenkūji, Edith joins forces with him and aids him against the Gamma. Edith also promises Ryū to involve his son Takeru in their expeditions as he saw the youth's potential in preventing war between their worlds. Edith later build the four Ghost Drivers and the heroic Eyecons, giving two to Argos and Daigo Fukami and a third to the latter's son Makoto.
In the present day, Takeru's death by the Katana Gamma forces Edith to modify Ryū's plan by infusing Takeru's soul into an Eyecon and giving him the Ghost Driver with a mission to collect the heroic Eyecons. Portraying himself as the playful and mysterious hermit (仙人 sennin), Edith takes up residence in the basement of Daitenkū-ji to keep watch on Takeru and his friends' missions while at the same time returning to the Gamma World to overseer the Gammas' progress. But when Adel succeeded his father and became a threat to their own people, Edith is forced to reveal his true colors by dragging the Gamma emperor to Earth to prevent him from harnessing the Great Eye's power. With his secret now exposed, saving Takeru and Alain from the Perfect Gammiser at the cost of his own body and return with another one while in the hermit's clothes. Edith also reveal that he could have revived Takeru during his first death, but the youth is now beyond his power is save after his lifespan ended and second revival. While the others were upset by that, Takeru instead thank Edith for his help with Makoto doing the same. It is revealed that his stasis capsule is hidden within Daitenkū-ji, with Yurusen revealed to be his pet cat, who also slept in the same capsule as him. He is currently decide to stay in Daitenkū-ji with Javel, instead of returning to their homeworld and takes Ryū's former position as the head priest of the Daitenkū-ji.
Edith possess his own Gamma Ultima Eyecon, which allows him to transform into Gamma Ultima Ebony (眼魔ウルティマ・エボニー Ganma Urutima Ebonī), a jet-black variant of the original Gamma Ultima form.
In the final battle against Adel and the Gammiser, he creates his own Ghost Driver and becomes a second Kamen Rider Dark Ghost, in order to open the monolith connection between human and Gamma's world completely. He was briefly mistaken by Takeru for Argos before Edith corrected the boy. Although trying to participate in the battle, his old age eventually forced Yurusen to withdraw him from the fight. However, it is unknown if the Dark Ghost he used is contains Argos' soul or another one.