personification of fear in Greek mythology

Phobos (Greek for "fear", is the root word of phobia) is one of the sons of Ares and Aphrodite in Greek mythology and the twin brother of Deimos. He is known as the god of fear, panic, flight and battlefield rout. He went with his father into battle, driving his chariot and spreading fear in his path. As a son of Aphrodite, goddess of love, each twin also represented the fear of loss.

The larger and innermost of Mars' two moons was named after him, and the other was named after Deimos.