"Darn it!"
At the moment he saw that twisted brilliance, the old guard realized he had carelessly fallen into extreme danger—in this cold, deep night, there was an existence that was unimaginably indescribable and unspeakable knocking at his door. What was even more fatal was that a few minutes ago, in order to extract secrets from the souls of two heretics, he had lit strong incense!
That incense was enough to construct the death illusions the caster wanted in the minds of the deceased and greatly enhance the caster's own perception and mental acuity, which allowed him to discern the presence of the Profound Demons from the slightestconscious fluctuations of the two heretics—the side effect, however, was that it briefly elevated his spiritual vision, making him now almost defenseless in facing the true nature of that Visitor.