Who is The Dowager/Mrs. Shizu Ogata from 1Q84 and what is their importance?

The Dowager, Mrs. Ogata, runs Willow House. Willow House is a western-styled home for abused women. Mrs Ogata opened her home for women when her own daughter committed suicide after suffering physical abuse. She employs Tamaru as a bodyguard, and Aomame as an assassin. The Dowager advises Aomame that she should not waste her youth.