"Lady Mary is one of the main characters in the Japanese manga series ""The Secret of the Friendly Duke"". She is a young noblewoman and the daughter of an aristocrat, Lord Grantham. Her character is known for her beauty, intelligence, and passion for justice.

Lady Mary's first appearance in the series is when she meets the protagonist, a young man named Katsuya, who is working for Lord Grantham as a servant. From this moment on, Lady Mary and Katsuya develop a close relationship, and she often confides in him about her hopes and fears.

Despite her privileged upbringing, Lady Mary is not content with the status quo. She possesses a strong sense of social justice and is always looking for ways to help those who are less fortunate. Her desire to do good is often met with resistance from her father, who believes that she should focus on marrying well and preserving their family's reputation.

Lady Mary is also a fierce advocate for women's rights. She is determined to break free from the expectations placed on her as a woman of her social standing and make a name for herself in the world. To this end, she educates herself on politics, economics, and other topics that are traditionally considered to be outside the purview of women.

Lady Mary's heroic nature is put to the test when she becomes involved in a dangerous plot to overthrow the ruling government. Despite the risks involved, she remains steadfast in her commitment to justice and is willing to risk everything to bring about change.

In conclusion, Lady Mary is a well-rounded and complex character who brings a sense of depth and realism to the world of ""The Secret of the Friendly Duke"". Her unwavering commitment to justice and equality make her a role model for readers, and her struggles and triumphs are sure to inspire and captivate audiences for many years to come."