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.

In the biography of the Supreme Demon God, there is a hidden character "Magic Master - Xia Houyi" whose identity is still unsolved at the end of the original game. With a rebellious personality but willing to help the protagonist fight against Chi You, where did he come from? The causes and causes that were unclear in the previous work all originated from an event. And the experience of this young age is the background of the story that this new game hopes to explain. It all started after Pangu created Wufang and Chaos in the early days. Nuwa and Fuxi invited Luohu to help create the world on the condition of sharing the three realms. Later, the three realms of clearing, fixing the soil, and transforming the wasteland were established. The power of clan eclipse then joined forces with Fuxi to start a battle of creation with Rahu. In the end, when Luohu was defeated, he and his family were defeated and returned to Youyin, and they waited for the opportunity of Xueqiu. And Nu Wa used seven-colored stones to form a strong sky, trying to seal Luohu and his clan forever in the secluded space left after the creation of the world, but it was unsuccessful because of the nine celestial movements. Luohu was afraid of Nuwa's surveillance, so he secretly built the sun and moon double envoys so that the Mingjie could build another nine armillary celestial apparatus to destroy the sky.