Castle: The Forbidden Divines is a story-driven role-playing game and a narrative prequel to Kalpa: The Sign of Omen. The game follows Xiahou Yi, a mysterious sorcerer who appeared in the earlier-released game. Set largely in the Western Regions, the story explores his relationship with Bingli and the events that determine their later destinies. Gameplay combines exploration, environmental puzzles, character development, equipment management, magic and semi-turn-based role-playing battles.