Nitori admires Rin badly, and can sometimes be jealous of the relationship Rin has with Haruka and the fact Rin calls Haruka 'Haru'. However, at the end of the first season Rin calls Nitori 'Ai' (his first name), which makes Nitori feel like a real teammate and friend.

Who is Rin's boyfriend free?

Aiichiro Nitori

He regularly accompanies Rin while he trains and enthusiastically helps him in any way he can.

Who likes Rin Matsuoka?

Rin likes both cats and dogs, though cats never seem to like him.