Percy Jackson and the Olympians: Legends

Phobos has long, red, streaky hair, red eyes, white face tattoos, and fair skin. Unlike his brother, Deimos, he wears knightly armor that's adorned with iron skulls and small spikes. Phobos, despite his reputation and personality, was stated to be to be very handsome and muscular, with these traits having been inherited from his mother, Aphrodite.

Percy Jackson admits that out of all of the gods and monsters that he disliked, Phobos "took the prize." He likes to taunt people and show them their fears. Despite his behavior towards Clarisse La Rue, Phobos isn't all that bad, as he accepted his other half-sister Piper McLean's request for help. However, this could be because Piper is a child of his mother, and so he isn't as aggressive with her as he would be with a child of Ares.

Phobos was born to Ares and Aphrodite. Along with his twin brother Deimos, Phobos would often accompanies Ares in battle. Years later, angry that their sister Clarisse La Rue was allowed to ride in Ares' chariot because they usually use the chariot, Phobos and Deimos decide to steal it from her. They then hide it in the Staten Island Zoo, and use it as bait to catch their sister and Percy Jackson. Phobos fights Percy, but is defeated and disappears. Years later following that, Underground, when Piper McLean and Annabeth Chase are fighting Mimas, Piper sacrifices her cornucopia to her brothers, Phobos and Deimos. Deimos's face came off the wall and crashed onto Mimas, killing him, indicating that the god had caused this action to get rid of the giant. Then Piper thanked her brothers and asked for a way out. Phobos then opened up a hole in the wall for them to get out along his twin.