A worthy prequel
Another excellent addition, set before volume 1 and the main series. Primarily focusing on Goblin Slayer's origins, there's also bits of the past regarding the first war against the demon lord.
If you ever cared about knowing the story behind the Goblin Slayer and the whole truth for his motivations and broken personality, this is the novel that casts light upon the unfortunate circumstances he encountered, along with his resilience and determination to enact vengeance.
A few prominent side characters from the main arc are included, some with "names" (more of titles or roles really) that are a bit different. It's still readily apparent who they are through, the illustrations and their characterizations are easily identified.
This is one of the more grim novels in the series, and while it can't hold a candle to the manga adaptation - it's certainly not bubbly or happy throughout. Strap on your armor and take the plunge into the first year of the Goblin Slayer, and how he became what he is.