Rogi is an artificial life-form created via alchemy and science, classified as a homunculus. They possess a slender build and an androgynous, handsome teenage appearance, with a face displaying artificially perfect symmetry. Notable traits include unnatural indigo hair and clothing featuring a coat adorned with numerous snaps, reinforcing non-human origins.

Operating within the organization Tartarus Lapse, Rogi has been involved for at least three years. During initial integration into the group, fellow member Senga provided instruction in car bomb construction and deployment techniques. This training established a mentor-student dynamic, leading Rogi to consistently address Senga as "Teacher."