The third goddess to be revealed in the series who resides in Tsukiyo's body but mostly in her doll Luna. Unlike her sisters, Vulcanus is almost blind, almost deaf and can't walk but she can move and possess objects telepathically. When Vulcanus takes over Tsukiyo's body, her hair becomes darker. During Keima search of the Jupiter Sisters by getting reacquainted with his past conquest, Vulcanus catches Keima getting friendly with Shiori through Luna.
Angered with the rumors that Keima is dating Kanon and now catching him three timing with Shiori behind Tsukiyo's back, Vulcanus vows to punish Keima to protect Tsukiyo by killing him but he manages to evade her attacks and confront Tsukiyo herself. Despite her efforts, Tsukiyo believes Keima's sincerity and Vulcanus reluctantly stops attacking Keima. After Tsukiyo kisses Keima on the cheek, Vulcan grows a pair of angel wings (much to Diana's chagrin) and is the first to be winged.