Who is Lady Seymour from Chains and what is their importance?

Lady Seymour is Elihu Lockton's rich aunt. She gives off the impression that she is a Loyalist to the outside world, but inside, she harbors deep sympathies for the Patriots as well as for the slaves. Lady Seymour treats Isabel with respect. She even feeds and cares for her when she is sick. At the end of the novel, Lady Seymour acknowledges wishing she had purchased Isabel from Madam Lockton when she had the chance.