And as for why she's so iconic in this series (aside from her having purple hair), well at least from my own personal point of view, it's her character background. A child born from rape, is looked down upon by everyone, with only one person making her feel like she's actually a person (Hayate). Finding out who her family really is and why she was ignored for so long, and having to prove to everyone that she's worth something. Overcoming so much to become a prodigy kunoichi and practically the most powerful ninja of Hajin Mon Sect to date.