Herpo the Foul is an outspoken villain from the Harry Potter series. He is an Ancient Greek Dark Wizard who is said to be one of the most powerful and influential Dark magic users in Harry Potter history.
Little is known about Herpo the Foul but it is shown that he was a very powerful wizard who used Dark Magic. He was best known as the first wizard to hatch a Basilisk. He is also the first wizard known to successfully create a Horcrux. Unlike Voldemort who created seven Horcruxes, Herpo the Foul created three horcruxes. It is unknown what those three Horcruxes were and when they were destroyed.
Herpo was also one of the earliest known Parselmouths. He might have been an ancestor of Salazar Slytherin because of his ability to speak to snakes.
It is unknown how/if he died and who destroyed his Horcruxes. Some Harry Potter fans think that his Horcruxes were destroyed by the venom of his own Basilisk, as it is one of the few things that can destroy a horcrux. Other don't even know if he died due to lack of information on him.
He was well known for influencing Lord Voldemort as he used a Basilisk to purify Hogwarts and he also sought Horcruxes to gain immortality.