Omikron: The Nomad Soul (Simply The Nomad Soul in Europe) is a Microsoft Windows and Dreamcast 3D adventure game developed by French developerQuantic Dream and published in 1999 by Eidos Interactive. It was released on October 31, 1999 for PC and on June 21, 2000 for Dreamcast. PlayStation andPlayStation 2 versions were in development for quite a short time but after the commercial failure of the Dreamcast version those were cancelled altogether.

Soon after the beginning of the game's introduction, the player begins the investigation in the Anekbah sector. He uncovers information that suggests the serial killer he is looking for is in fact not human but actually a demon. When members of an apparent underground, anti-government movement contact the player and confirm his suspicions, the investigation deepens and uncovers information; one of Omikron's chief police commanders, Commandant Gandhar, is a demon pretending to be human and lures human souls into Omikron from other dimensions by way of the Omikron video game. Kay'l 669 asking the player to help him was a trap: supposedly, if the in-game character dies, the real human playing the video game will lose their soul forever. Despite many assassination attempts on the protagonist's life by other demons working behind the scenes, the player destroys Gandhar with supernatural weaponry.
After this brief victory, the player is invited to join the mysterious anti-government movement named "The Awakened" (referring to the fact the characters have "awakened" from the lies and drugs of the government). The Awakened work in tandem with an ancient religious order who are led by Boz, a mystical being that exists in purely electronic form on the computer networks of Omikron. The Awakened refer to the protagonist as the "Nomad Soul" since he has the ability to change bodies at will. The Nomad Soul learns afterwards that what is going on in Omikron is merely an extension of a thousands-of-years-old battle between mankind and demons led by the powerful Astaroth. Astaroth, who was banished to the depths of Omikron long ago, is slowly regenerating power while using demons to both collect souls and impersonate high members of the government; he believes he can eventually take complete control and move across Phaenon and the Universe beyond. Only by harnessing ancient, magical technology and by re-discovering several hidden tombs underneath Omikron's surface, can the Nomad Soul hope to discover how to destroy Astaroth, return to his own dimension, and prevent his soul from being captured by demons.

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Developer: Quantic Dream

Publisher: Eidos Interactive