Manga Volume 1

Summary
Tate no Yusha no Nariagari - Vol.1 (MF Comics Flapper Series) Manga. Japanese Title: 盾の勇者の成り上がり 1 (MFコミックス フラッパーシリーズ) Iwatani Naofumi is summoned to another world to become one of the 4 heroes, namely the Shield Hero. Starting out with poor popularity and labeled as the weakest, Naofumi found himself betrayed on the 3rd day of his adventure. Losing faith and money, all that left is just his shield.  Amazon