Mordecai is a key figure in the biblical Book of Esther. He is known for his loyalty and bravery, particularly in protecting his cousin, Esther, who becomes the queen of Persia. Mordecai uncovers a plot to kill the king, which ultimately leads to the saving of the Jewish people from a decree of destruction. Mordecai's story highlights themes of courage and faith. He refuses to bow to Haman, the king's advisor, who seeks to harm the Jews. His actions inspire Esther to reveal her identity and advocate for her people, showcasing the importance of standing up for what is right.