Goblin Slayer Side Story: Year One

Goblin Slayer Gaiden: Year One (ゴブリンスレイヤー外伝：イヤーワン) is a prequel of the Goblin Slayer Series. The story was written by Kumo Kagyuu and the art was done by Kento Sakaeda. It began serialization on Sep 15, 2017 in Young Gangan.

Plot
Prequel series revealing Goblin Slayer's past and the events which led him to become an adventurer with the one and only purpose of annihilating all goblins from the world.