Goblin Slayer Side Story: Year One, Vol. 4 (manga) — Kumo Kagyu

After protecting a village from a horde of goblins, a certain young man is 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. He has the ring appraised by an eccentric magician known as Arc Mage, who, in exchange, requests his assistance in compiling a monster manual for the Guild. What section will he help research? The one about goblins, of course! With a single ring -- and a single light -- a brand-new story begins.