Hathach was a royal eunuch or attendant assigned to Queen Esther who carried messages between Esther and Mordecai during Haman's crisis.
Biography
Esther 4 says that when Esther learned of Mordecai's mourning, she summoned Hathach, one of the king's eunuchs appointed to attend her, and ordered him to learn what was troubling Mordecai. Hathach repeatedly carried messages between them, including Mordecai's explanation of Haman's decree and his appeal that Esther go to the king on behalf of her people. Through Hathach, Esther communicated her decision to fast and risk approaching the king.
Biblical Significance
Hathach played a quiet but essential intermediary role at the turning point of Esther's story. His faithful transmission of messages enabled Esther and Mordecai to coordinate their response to the threat against the Jews.