Immortal Trapping Formation!
Although the name sounds imposing, easily conjuring images of the mythical Immortal Trapping Formation from Huaxia legend—a powerful formation capable of dooming even Immortals—the actual power of this formation was worlds apart. Furthermore, the Onmyoji controlling the formation was not particularly strong. Even with the sacrifice of Life Force and the reliance on a treasured artifact from his Sect, the explosive power unleashed could, at most, suppress a Mysterious Level Medium Tier Martial Artist.
If it were used against a Mysterious-level Upper Tier Martial Artist, the Onmyoji would struggle significantly. The formation would, at most, hold for a few minutes before being broken.