The Phantom Shadows of Di Renjie

During the Xianqing era of the Tang Dynasty, the imperial jade seal vanishes from the heavily guarded palace, leaving behind only a black token engraved with the characters "Phantom Shadow." Di Renjie, the chief judge of the大理寺, is ordered to solve the case within a strict deadline, only to discover that this is no isolated theft—a poisoning at a Luoyang banquet, a corpse hidden in a clay statue at the Longmen Grottoes, and the massacre of thirteen members of the He-Luo Escort Agency all point to the same mysterious organization. In the martial world, "Phantom Shadow" has three ranks: the Human rank is invisible, the Earth rank takes lives, and the Heaven rank never appears. The wandering hero Ouyang Bei, searching for his missing master, goes from sword-crossed enemies to life-or-death allies with Blue Luosha, the top agent of "Phantom Shadow." The "Raksha Rope" in her hand is linked to a century-old secret left by Emperor Yang of Sui—the imperial jade seal might be a fake, with the real one hidden beneath the old course of the Yellow River. As Di Renjie unravels the clues, he finds that behind "Phantom Shadow" is none other than the reigning emperor. Emperor Gaozong has set up this shocking scheme, using the theft to lure out snakes, eliminate those in the know, and seek the true "Mandate of Heaven." Meanwhile, the powerful Empress Wu and the remnants of the former crown prince's faction each harbor their own schemes in this game. When the final veil of truth is lifted, Di Renjie faces a choice harder than solving the case... — Description from novelcodex.org