Ore no Osananajimi wa Joshikousei de Yuusha summary: High school soph.o.m.ore Shimoyama Yuuki’s childhood friend Arina goes on a journey to defeat the Demon King as a Hero on her 17th birthday.Worried about his all-too-unsociable childhood friend, Yuuki went along with her on her journey, however…Fantastic obstacles await them on their destination, or they should be, but Arina is behaving strangely sometimes…