Seoul, South Korea, Sept. 26, 2025 (GLOBE NEWSWIRE) -- GRAVITY Co., Ltd. (NasdaqGM: GRVY) (“Gravity” or “Company”), a developer and publisher of online and mobile games, announced that Ragnarok Idle Adventure Plus (Chinese Title: 仙境传说：梦想天空), a Vertical Idle MMORPG game, received an ISBN code by Chinese government disclosed on September 24, 2025. Ragnarok Idle Adventure Plus marks the third ISBN in 2025 following 仙境传说：初心 (PROJECT ABYSS, Tentative English Title) in January and 仙境传说之约定好的冒险 (Ragnarok: The Promi ...