In the final episode, Kotoura wins a Luna from a Luna catcher toy-grabbing machine, and hugs it happily.
Luna is a purple thing that is naked and that Manabe often fantasizes about. Luna is first shown in Manabe’s mind as Kotoura approaches him, dancing around and duplicating itself. We don’t know much about it, as it is not shown a lot in the anime. It is also shown on a poster in Manabe’s room. It appears to be a TV show character.