Issei Ariga is a tall, thin male character with medium-length black hair and grey eyes. He works as a hairdresser and beautician. His life undergoes a significant shift after being possessed by the cursed weapon Nebestigma, which transforms him into a Chrysalis.

The murder of his sister, Sanae, by Arnys becomes a driving force in his life, compelling him to seek revenge. He commits the appearance of her hair to memory as part of this pursuit. His first appearance involves expressing a desire to kill the woman with the most beautiful hair. Arnys later approaches him for a haircut, forcibly binding him with Nebestigma, an act that triggers his transformation into a Chrysalis.

To avoid Yasuko's advances, Issei joins the Shoshidai organization and enters cold sleep to suppress his Chrysalis state. He is intermittently awakened for missions, including one to eliminate a Busoma, though he is ultimately defeated by Zoltogei. After this failure, he departs from Shoshidai and returns to his previous life as a hairdresser.

Issei is characterized by an unwavering focus on avenging his sister and a direct, blunt demeanor. In his Chrysalis form, he possesses enhanced healing abilities. His expertise as a hairdresser is evident in his precise and refined haircuts, which he crafts using criticism as a tool for perfection.