As something unknown was observed, the silhouette of the current target within Motan's sight would shift. After numerous confirmations with Father Owen, he has now basically been able to identify the specific features of plague carriers — that is, green!
If the snow-white silhouette exhibits green somewhere, whether it is dark green, light green, grass green, or jade green, it generally means the other person is infested. Those severely afflicted are glowing green all over, while those contracted in certain spots but not yet widely spread would only exhibit spots of green…
Fortunately, there has not been a case of how disastrous it would be if the forehead were infected so far.