Roka

He's the best friend to Yamato and in many ways his second conscience. Roka was always afraid of the things Yamato would do because it tends to be dangerous or morally conflicting. When Yamato chose to leave their village, Roka tagged along for the journey. Through their adventures together between battling Sky Warriors and avoiding danger, he learned to become a stronger person. By the time they returned to their home village, Roka has become wiser and braver than he used to. He returns in After War as a scholar and wears glasses.

Source: Wikipedia