Darius II is a 1989 arcade video game developed by Taito. It is the direct sequel to the 1987 Darius. It was later released as Sagaia in Japan in 1991 for the Game Boy as well as non-Japanese ports. A remake was released for the PC Engine Super CD-ROM as Super Darius II in 1993. A Mega Drive conversion was released in Japan in 1990; it was later released for the Genesis in the United States and Brazil in 1991, where it was renamed Sagaia. Changes include a boss rush mode (via a code) and various modifications to levels and mechanics, such as the boss Steel Spine being moved to another level and the boss Killer Higia being replaced with a similar creation called Nehonojia. This conversion does not support two players, so the ability to choose between Proco Jr. and Tiat Young was added; Proco plays like normal, while Tiat starts every life off with one power level to every weapon. A Master System conversion, developed by Natsume, was released in Europe and Brazil in 1992, also titled Sagaia. It is somewhat based on the Mega Drive port, and while Tiat Young and her abilities are still present (though even more limited), many zones (and thus bosses) have been completely removed. The Super CD-ROM version features an entirely new set of bosses, major changes to levels, and a fully arranged soundtrack including new songs.

The planet Darius, which formerly boasted a very advanced civilization, has been destroyed. Proco and Tiat escaped from Darius in search of a new world. They started a new civilization on the planet Olga. The descendants of Proco and Tiat happened to pick strange radio waves being emitted from the Milky way galaxy. The strange radio waves were an SOS from the planet Darius where their ancestors used to live. Having discovered the source of the strange radio waves, the immediately boarded the Silver Hawk, whose power had been greatly increased, and took off for the Milky Way. A fierce battle ensued on the planets of the Milky Way and in outer space in order to save the inhabitants of Darius from destruction.