Harmonthrep was a gifted Centaur seer who lived in the Forbidden Forest in the 1400's. He made several notable prophecies, the first and most famous of which foretelling the Heir of Slytherin, Lord Voldemort. Three other prophecies followed, each one proclaiming the coming of the Heir of Gryffindor, Hufflepuff, and Ravenclaw.

Harmonthrep's likeness was used for the Fountain of Magical Brethren.