All of the Hsien have this power, from the lowliest Hirayanu to the mightiest Kamuii. As a general rule the shinma only calls on this power when terrifically angered or when what's called for is a serious show of force, even if it's a bluff. When using Mask of Shintai, hirayanu becomes twisted and horrible while the kamuii become to magnificent to behold. Any unusual feature becomes exaggerated and with the animalistic hirayanu this can end up in the grotesque. For a Kamuii this ability could be likened to a Sidhe calling on the Dragon's Ire; both are resolute and terrifying, causing viewers to bend in complete supplication. Those seeing a Hirayanu will flee in terror.
The Hsien decides how much Yugen they want to spend on the Mask of Shintai effect. Then all present must make a Willpower roll, difficulty 7 for mortals, 6 for other Shen, and 5 for other hsien. Successes must equal or exceed the amount of yugen invested in the effect. Failure on the roll means the observer either flees in terror from the Hirayanu or bows in complete subjection to the Kamuii. The effect lasts for a number of turns equal to the difference between the number of yugen spent and the successes won by the witness.
In a Dragon Nest the witnesses must score two successes for every point of yugen spent to resist the effect.