Agrios, son of Polyphonte and brother of Oreius, was one of the two bear-like humans that Polyphonte conceived.

Polyphonte wanted to be a virgin, and in order to achieve this, she fled to the mountains to become a companion of Artemis. Seeing this Aphrodite was enraged because she thought that Polyphonte was neglecting her duty as a woman. As a punishment, Aphrodite drove Polyphonte mad with lust for a bear. Artemis was disgusted and turned the wild against her. Polyphonte then fled in fear of her life back to her home.

Once she was home, she conceived Agrios and Oreius. Agrios and Oreius turned into huge, strong men.

Zeus hated Agrios and Oreius and had Hermes punish them. Agrios and Oreius almost lost their hands and feet but were then saved by Ares, their great-grandfather. Ares persuaded Hermes to soften their punishment by turning them into birds.

Agrios was then turned into a vulture.