俺の幼馴染は女子高生で異世界の勇者なんだがそれだけじゃないっぽい (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…