About the Goblin Slayer Side Story Year One Manga Volume 4 (Mature)

After protecting a village from a horde of goblins, a certain young man has been called 'Goblin Slayer' for the first time. One day, while slaughtering yet another group of goblins, he finds a ring that glows with a mysterious light, which he has appraised by an eccentric magician who lives outside town known as Arc Mage. She, in turn, requests his help in compiling a bestiary for the Guild. He is put in charge of the section on-of course, goblins. With a single ring, and a single light, a brand-new story begins.