is a Japanese science fiction video game series created by Tetsuya Takahashi. The first entry was developed by SquareSoft, and subsequent entries have been developed by Monolith Soft, a company founded by Takahashi after he left Square in 1999. While no direct story connections exist between the various games in the series, they have common thematic links and all sport the "Xeno" prefix, which Takahashi has variously described as a means of identifying his games and a symbolic representation of the series. All the games in the Xeno series take place within a science fiction setting despite occurrences of fantasy elements, with its stories frequently featuring psychological and religious themes.