Who is Anatasia Filippovna (Nastassya) from The Idiot and what is their importance?

Anatasia Filippovna (whose nickname is Nastassya) is a femme fatale, yet Dostoevsky also presents her as one of the book's tragic figures, alongside the Prince and Rogozhin. Totsky took her in after a fire killed both of her parents. He paid for her schooling and raised her in his household. As she grew up, her beauty attracted her to Totsky as a woman and she became his mistress. However, her unpredictable character frightened Totsky and, worried she would ruin his reputation, arranges for her to marry Ganja. During the novel, Anatasia proves too clever for her guardian, and beyond living her life for just money and position in society, she runs off with Rogozhin.