Tate no Yuusha no Nariagari

Naofumi Iwatani is summoned to the kingdom of Melromarc with 3 other men to become the 4 Cardinal Heroes against recurring Waves of Catastrophe. The others receive a sword, spear, and bow, while Naofumi is left with the Shield and immediately treated as the weakest. A betrayal and false accusation then destroy his reputation, leaving nearly the entire kingdom hostile toward him.

Unable to trust people, Naofumi begins building strength on his own terms and purchases the contract of Raphtalia, an enslaved demi-human girl, to fight beside him. Their relationship gradually becomes a partnership based on trust rather than ownership. As the Waves approach, Naofumi must protect a country that despises him while rebuilding both his name and his ability to believe in others.