Hebikawa kinda reminds me of Accelerator from To Aru.
Hebikawa admired kindness and beautiful souls, but when confronted with the dark reality surrounding her she immediately crumbled and became the unkind and ugly person she is now.
Accelerator wanted to live his life like a normal kid and make friends, but when confronted with the dark reality of the Academy City and all the attention his powers drew to himself, he immediately crumbled and became the unhinged murdered they labeled him as.
Despite that, both Hebikawa and Accelerator have this admiration for the people they want to hurt. Hebikawa wants to expose Kusunoki's dark side because she reminds her of her former figure of admiration; meanwhile Accelerator kept calling Touma "hero" during their fight, and even after that never called him by name and kept projecting this ideal of a hero onto him.
Now, Accelerator went so far into the deep end that he even chastised Touma for not having saved someone Accelerator held dear, even though Touma could never have done so in the first place. It took Touma giving him a reality check and telling Accelerator to become the hero his friend needs for him to understand that Touma is just a normal guy that didn't crumble in the face of adversity like he did, and now decides to try being a good person once again.
Will Hebikawa follow that trend set by Accelerator or will she go further down the dark path and actually become a villain?