Gaia (株式会社ガイア, Kabushikigaisha Gaia) was a video game developer formed by Kouji "Cozy" Okada following his departure from Atlus in 2003. Okada is best known as one of the co-creators of the Megami Tensei franchise, along with its subseries Devil Summoner and Persona.^[1]

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Monster Kingdom: Jewel Summoner was the first game produced by Gaia. Gaia also assisted Game Republic with Folklore's monster-creation system, and its original title was Monster Kingdom: Unknown Realms. Another Gaia game, Coded Soul: Uketsugareshi Idea, was released in 2008 with numerous gameplay elements in common with both Jewel Summoner and Folklore. The developer's website was inactive in 2010, suggesting it closed and its final project, Cosmic Walker for the Wii, was cancelled.^[1]