Rei says or does something
Natsuyu gets jealous because she wants Rei all to herself
Otaku-kun helps Natsuyu in some way
Natsuyu gets Rei/s attention
Although Otaku-kun is ever present he has zero interest in our two main girls, he wants them together, and does evrything he can possibly do to help them get together from giving them tickets to go see a movie together to dressing up as a maid for a maid cafe and taking Natsuyu's place in the cafe so Natsuyu can run away to go and see Rei preform in a fashion show.
Over the course of the manga other characters do get introduced besides our main three but they are soo minor it is not reallt that notable.
