Nessus

A Centaur. Nessus was one of the Centaurs who fought against the Lapiths, at the wedding of Peirithous and Hippodameia. When the Lapiths drove the Centaurs out of their kingdom, most fled to Mount Pholus at Arcadia. Instead, Nessus headed west to the Evenus River in Aetolia, where he acted as a ferryman.

Nessus encountered the hero Heracles, who was leaving Aetolia with his wife, Deïaneira. Nessus offered to ferry Deianeira across the Evenus. Heracles accepted and went ahead, but Nessus tried to rape Deianeira. Hearing his wife's cry for help, Heracles mortally wounded the Centaur.

Dying, Nessus instructed Deianeira to keep his blood, which he falsely told the princess that it was a powerful love elixir. If Heracles was to stray from his marriage with her, she should smear his blood on the hero's shirt, and Heracles would love her again. Deianeira didn't know the poison that killed Nessus, came from the deadly venom of the Hydra. This blood would later kill Heracles.

See Deianeira and the Death of Heracles.