Greyworm
Jacob Anderson plays Grey Worm, the elite fighter and leader of Daenerys’ Unsullied Army. In the novels as well as the show, Grey Worm was castrated when he was a slave during childhood, so in the show they make him appear to have very boyish features for his age.
They do this by keeping him totally clean-shaven except for his head during filming. He also had to keep his body in tip-top shape considering that he wears the most revealing armor in the entire show, with his arms exposed at all times.