Is she really a professional assassin ? Is she really called grim reaper ? Because for now she doesn't deserve those titles. She got caught the two times she sneaked out, she got caught by that Gin-like guy because she dropped the act as soon as she got out of the room, and she didn't even sensed him spying on her. She seems quite incompetent compared to her reputation, the only noticable thing she did was using the tracking perfume.
She's a small fry compared to assassin-like main characters that I saw in other series.