The purpose of eyebrows is to keep sweat out of your eye. Due to this, I've deduced that Tien should have an eyebrow above his third eye. It only makes sense.

P.S. Tien with blue eyes looks fucking sick as hell.

>>280768983 (OP)
draw where you think the sweat glands are located

>>280768983 (OP)
Is that really the purpose of eyebrows opposed to communication?

The reason I say this is because I don't feel it works that way, they're not a trench, they slow down sweat that will just drip down later I feel, they don't divert it to the sides at all.

Furthermore, the area under eyebrows sweats just as much.