Mutsuki Asagi is a second-year student at Gehenna Academy and a core member of the Problem Solver 68 club, where she holds the position of chief of staff. She is best described as a devilish troublemaker who takes genuine delight in causing mischief and committing acts of wrongdoing without hesitation or guilt. This sets her apart from her childhood friend, Aru Rikuhachima, who often wrestles with a conscience despite her own criminal bravado. Mutsuki understands Aru better than almost anyone and frequently teases her, but their close bond remains a defining part of her character. Her motivation stems from a simple love of excitement and chaos; she does not need a grand cause to act, only an opportunity for fun. In the story, she acts as the assault activist and go-getter of Problem Solver 68, eagerly pushing the group into schemes and confrontations. She is known for carrying a machine gun and a large bag filled with explosives, reflecting her hobby of bomb collection. Physically, she is 144 centimeters tall with long gray hair, pink eyes, and pointed ears, and she is often seen with a halo, a bag, and a cheerful, mischievous expression. While the anime adaptation does not show significant personal growth beyond her established personality, her role remains consistent as the energetic, morally unburdened engine of her team. Her notable abilities lie not in special powers but in her sharp understanding of people, her fearlessness in the face of trouble, and her willingness to act where others hesitate.