Deronda is given up by his Jewish mother when he is a toddler and is then raised by Sir Hugo Mallinger. Deronda receives the education of an Englishman but doesn't know how he wants to spend his life. After he rescues Mirah Lapidoth from the river, his life is put on a new trajectory. This leads to his learning about Judaism and his acceptance of his role as a future leader in the Jewish community.
As a beautiful girl of 20, Gwendolen wishes only to please herself and be admired by men, although she is not keen on marriage. After her family is impoverished, she forces herself to marry the aristocratic Grandcourt, who breaks her spirit and treats her like his property. In the end her hardship teaches her to be a kinder, humbler person.
One critic has called Grandcourt the personification of German philosopher Arthur Schopenhauer's concept of a malignant will. Others might identify Grandcourt as a fully realized sociopath who has no ability to love other human beings. Sociopaths are often bored because they lack feeling, and this is the case with Grandcourt. He marries Gwendolen to break her and finds pleasure in making her his slave. In the end his overconfidence leads to his death when he falls off a sailboat and drowns.
Mirah was kidnapped by her father when she was a little girl. He raised her to become a talented musician who can earn money. When her voice is injured because he pushed her too fast, he tries to sell her as a mistress to a rich count. Mirah runs away, but when she can't find her mother and brother in London she tries to kill herself. Daniel helps her create a new life and eventually marries her.
Mordecai believes the Jewish people must have their own homeland, and he plans to devote his life to this cause. While heading for the Middle East, he is called home by his mother after his father kidnaps his younger sister Mirah and leaves his mother saddled with debt. Mordecai is a penniless consumptive (he has tuberculosis) when he meets Deronda. He conceives that he and Deronda are twin souls and Deronda will carry on his work for the Jewish people after he dies.