CAINS STUDIO, known in Japan as Act of Cain (カインは行動する, Kain wa kōdō suru lit. Cain's Act), is an psycological dark fantasy visual novel game by the franchise: duology. In 2004 the game reached the publishing outlook, then hit revision in graphical use and story elements by 2021 of July. It is an direct story reaffirmation of the game within the same universe: The Maiden (処女, Maiden lit. Unique Women), which released in 2021 three months prior to the game's revision upload.