Atlus Co., Ltd. is a Japanese computer and video game developer, publisher and distribution company based in Tokyo and a subsidiary of Sega Corporation. It is best known for developing the role-playing video game franchise Megami Tensei and the surgical simulation-visual novel franchise Trauma Center. Megami Tensei was a Nintendo Entertainment System video game published by Namco and based on a trilogy of novels; after the second game, Atlus formed to publish the series.