Ore no Osananajimi wa Joshikousei de Yuusha (Associated Names)

High school sophomore 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 behaves strangely sometimes…