Goblin Slayer Side Story: Year One manga volume 5 features story by Kumo Kagyu and art by Kento Sakaeda.

When Goblin Slayer and Arc Mage continue their goblin research with a dissection of one they killed in the ruins, they discover something new about the creatures. Rookie Warrior also heads into an abandoned mine with a party of inexperienced but fearless adventurers, attempting to master his weakness, but what will he do when they come under attack from yet another new threat?!