Maybe the only thing i can say is
He is dark, and objects around him is light so it kinda give him some light
He himslef doesn'e emit light
Except this one when he cast a Super Kitakaze chip
Also, his face is white, while his helmet is dark colour
Colour differences could make some kind like a shadow too
And, there are some space between his face and the frontmost part of the helmet
So, if we see him from far away, with some light objects or light coloured things around him i guess you'll gonna see he has some kind of shadow on his inferior palpebrae