You were summoned to this world to fight the waves, but it was an accident. Let's go over more details later, and Welcome to the world or Rising of the Shield Hero, where the Kingdom of Hogwarts had summoned 4 Cardinal Heroes to defend the Kingdom from the Waves:

The Sword Hero Ren Amaki

The Bow Hero Itsuki Kawasumi

The Spear Hero Motoyasu Kitamura

the Shield Hero Naofumi Iwatani

Naofumi's Team members: Raphtalia (Demi-human), & Filo (Godbird), Rishia, Ren (human/Dragon)