Phelios (フェリオス, Feriosu) is a 1988 vertical scrolling shooter released for the arcades in Japan by Namco. It runs on Namco System 2 hardware. A home version for the Mega Drive/Genesis was released in 1990. The game features a plot loosely based on Greek mythology. The player takes control of the knight Apollo, the god of the sun, who sets off on the legendary winged horse Pegasus, to rescue his lover, Artemis, the goddess of the moon, from the Titan, Typhon (the one that Zeus dropped a mountain on). The game takes names and little else from Greek mythology in which Apollo, god of the sun, was actually Artemis's brother. The game shows players an Artemis that acts as an stereotypical princess (but in Greek mythology, she was the goddess of the hunt, and took pride in never being with any man).

The arcade version of this game was never released in the United States, due to Artemis's "bondage/torture" scenes, which were shown between each stage, and were similar to those from the new version of Namco's own Rolling Thunder; while no nudity is shown, the scenes were still somewhat "strong" to be shown in an arcade game during the early 16-bit era. This game's score display also gives the illusion of allowing values which do not end in "0", like Hopping Mappy, Bakutotsu Kijūtei, and Metal Hawk did before it - however, the smallest point value that the game can award to a player for killing an enemy is 10.