Gale was omniscient. Well, only in the couple of hundred-metre radius in the surroundings. His Spiritual Sense could cover only that much.
This ability wouldn't let him see—that was the job of the eyes—but it could enable him to detect the tiniest ripple in the natural energy flow. Naturally, any practitioner or even a normal person emitted a unique aura all the time which leaves a sign wherever they visit.
Although sneaky spy or assassin-type individuals trained to keep that unique aura in check, Gale couldn't anticipate another unique individual like that Ghost on his back.
So anyone below the gold rank would be detected under this spell unless they have a unique state like that Ghost.
