Nagi is a confident boy who is popular with the girls his age, and seems to be a bit of a playboy. His maturity and knowledge concerning girls belies his age, convincing even Hodaka to refer to him as "senpai." He possesses a caring side and a sense of self-awareness evidenced by his desire to see his sister experience a normal teenager's life, as she does a lot for him.
Nagi is an elementary school student who Hodaka witnesses smooth talking girls on the bus. They are properly introduced by Hina when Hodaka discovers he is Hina's younger brother. He does what he can to help his sister in her Sunshine Girl ventures, and is supportive of Hodaka's feelings towards her.
Behind the Scenes
He is voiced by Sakura Kiryu.
Amano (天野) means "sky field", while Nagi (凪) means "calm" (weather).