"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. Due to her awful past of being bullied, her self-esteem was crippled, and the effect lingered until now. Thankfully, she was saved by Aru, and ever since then, she's been loyal to her."

A supporting antagonist of volume 1, I imagine an extremely gloomy, but soft voice that can turn erratic if needed for this character, since this is a fandub, feel free to any little quips you feel fit! Will have some lines in the dub. 

Japanese voice reference can be found here: https://bluearchive.wiki/wiki/Haruka/audio