An "entry-level employee" of Problem Solver 68 and 1st year student at Gehenna Academy. Despite being shy and possessing cripplingly low self-esteem, her ideas and determination to commit any act makes her the scariest and most dangerous amongst the already erratic fixers.

She has been bullied ever since childhood because of her dark and gloomy personality, but was able to escape that fate thanks to Aru. Currently, Haruka is the youngest member of Problem Solver 68.