The modern city "Yunzhou City" appears to be an ordinary metropolis with prosperous science and technology, but in fact it is the core node of the revival of ancient spiritual veins. Thousands of years ago, in order to resist the invasion of the "Erosion Spirit Clan" from outside the territory, the ancient human martial arts masters condensed the "Spirit Seal" with their own essence, blood and soul, and sealed the spiritual veins and the Erosion Spirit Clan underground in the city. As a result, the inheritance of ancient martial arts was broken, and humans gradually forgot their extraordinary power.
In the past ten years, cracks have appeared in the spirit seal, and the power of spiritual veins has penetrated the surface of the earth. Some humans have awakened "seals" (ancient runes emerging from the palms of their hands). Those who have awakened are called "seal warriors." Seals are divided into three categories: "Martial Seal" (strengthening the physical body, controlling martial arts), "Spirit Seal" (controlling spiritual energy, performing secret arts), and "Tool Seal" (communicating with ancient weapons and objects, awakening weapon spirits). Each type of seal has nine realms, corresponding to "Sealer - Seal Master - Seal Master - Seal King - Seal Emperor - Seal Master - Seal Saint - Seal Emperor - Seal God".
The resurgence of spiritual veins triggers "urban secret realms": spatial cracks connected to underground spiritual veins appear in various places in Yunzhou City (old cities, abandoned factories, deep mountain parks, etc.). The secret realms contain ancient martial arts inheritance, spiritual vein crystals, but there are also escaped remnants of the Erosion Spirit Clan (monsters that look like condensed black mist, and make a living by sucking spiritual veins and human seals).
