@lyanhyrt
ranko just wants to make him a better person so makes him work out and shit. nene was childhood friend that he promised to marry when they grew up. kashi started liking him when he put those muscles ranko gave him to use when she got heat stroke. and the trap likes to tease him because kashi likes him.
@lyanhyrt Kashii has liked him from before the manga starts as reveled in The First Regret. She liked him basically because he was kind but she couldn't really admit she liked her m until recently. I believe the train was a scheme to be alone with Junichi. Yuki, the trap, likes him because his sister likes him. Ranko doesn't like him, she's a lesbian who loves Yukana. Ranko however is trying to make him a better person though. Nene has liked him since they were kids.