is a series of console role-playing video games and other supplementary media created by Sega. The series debuted in 1987 on the Master System with Phantasy Star, and continues into the present with Phantasy Star Online 2 and other extensions of the Phantasy Star Online sub-series. Each of the games in the series features a science fantasy setting featuring a cross-genre combination of magic and technology.
The first four games in the series are set in or related to the fictional planetary system of Algol, and are single-player turn-based role-playing games. Later games in the series are chiefly action role-playing games, and some contain massively multiplayer online game elements. There are currently four distinct Phantasy Star subseries, each set in their own universe. Cameos or nods to other subseries may appear, and there are concepts and terminology shared across them, similarly to Suikoden, Breath of Fire, Dragon Quest and Final Fantasy.
The original series takes place in the Algol Solar System, which consists of four planets: Palma, a fertile agricultural world; Motavia, a desert planet; Dezoris, an ice planet; and the mysterious Rykros, whose elongated orbit brings it within visible range only once every thousand years. Players travel to all four planets throughout the series, interacting with each unique set of inhabitants and discovering the secrets to the solar system's genesis, which is irrevocably tied to an ancient conflict.
Phantasy Star was the first installment of the series, released for the Master System in Japan on December 20, 1987, and then in the United States and Europe in 1988. It introduced players to the planets, races, and lore of the series. The game follows the adventures of Alis Landale, a young woman from Palma. After Alis's brother Nero is killed by the formerly benevolent government of King Lassic, Alis embarks upon a quest for revenge. She is joined in her rebellion by a muskcat named Myau, a warrior named Odin, and a wizard named Noah.