Dai Katana is a light novel series written by Kumo Kagyu, the same author who is currently writing the main Goblin Slayer series. It is a prequel to the main series, and a consequential one at that; based on an image from episode 5 of the anime, this is almost certainly the story of the party that defeated the Demon Lord more than a decade before the main story begins, and Female Bishop is almost certainly the younger version of Sword Maiden from the main story. (Unless there are two characters in this setting that are blond priestesses who are mostly blind and have a deep-seeded fear of goblins, of course.) Kagyu is dodgy about admitting to this in the Afterword, but he also says nothing that would deny it, either.

The most immediately evident oddity about the story is that, unlike the main series, it is told entirely in second-person point of view, with “you” being the unnamed samurai who leads the adventuring party. (He is commonly referred to as “Captain” by the others, but that does not seem to be his official title.) Most of the protagonist's dialog is described rather than said in quotations as well. This makes for a very odd effect, as if the protagonist is intended to be the self-insert for the reader, although the protagonist is not at all the blank slate that would normally be expected in such situations. He has a distinct character, one which shows most amusingly in the ever-shifting way he refers to his cousin: he emphasizes that she is his “second cousin” whenever he finds her behavior to be annoying but typically refers to her just as his cousin when he finds her actions or abilities to be admirable. Kagyu does continue his long-standing practice of using only the titles of the characters rather than their actual names, though the characters evidently have real names.

Beyond that, the story is a very standard tale about the formation and early adventures of a novice tabletop fantasy RPG party. Fledgling adventurers come to a Dungeon town, form up into a group of six individuals with diverse skills, and tackle the dungeon. Duties and marching orders within the group are assigned and performed according to the most fundamental tabletop RPG tactics: the Scout deals with locks, traps, and watching the rear, the wizard and cleric are in the second of two ranks, and so forth. The Dungeon has rooms where monsters guard treasure chests, wandering monster encounters can happen, measurements sometimes happen in squares, and terms like “level,” “hit points,” and “critical hit” get thrown around.

None of this should be surprising to anyone who has read the main series novels, but this series may be even more of a slave to tabletop RPG conventions, and that is only interesting to a point. The story treads very close to just being a recounting of a few Dungeons & Dragons game sessions, so much so that I would be surprised if such sessions are not the source of the story. Only some downtime dialog scenes vary from that impression at all, and even those easily fall into the category of standard filler. While this does not necessarily provide a barrier to telling a good story, being locked into having to justify game mechanics in non-game terms feels constraining at times.

At least Kagyu does prove good at creating ambiance, and that is the novel's saving grace. Based on his descriptions, the Dungeon of Death is a more immediately oppressive place than the Dungeon in the DanMachi setting, with even a built-in mechanic for explaining why parties would rarely encounter each other despite the Dungeon levels not seeming all that huge, and why groups larger than six (the standard size limit for tabletop RPGs in convention or tournament events) can be counter-productive in the Dungeon. Even discounting the disturbingly high death rate, this is an intimidating place rife with danger, to the point that even a little experience can change a person. He also effectively equates the RPG concept of hit points to fatigue factor, and how leveling up can be as much about building endurance for dealing with the dangers of adventuring as anything. Most importantly, he conveys the sense of how dangerous dungeon-delving can be, even more so than in the main novel series.

Yen Press's release of the novel provides character portraits and brief profiles at the beginning (including alignment and class identifiers) and the standard assortment of black-and-white illustrations throughout. Notably, one of them provides a picture of the “wire frame” description of the Dungeon, which looks like it was meant to harken back to very early 3D first-person perspective computer RPGs. It ends its mere 186 page length with the aforementioned Afterword. I do have to wonder about one translation point: was “Non-Prayer Characters” really the intended meaning? If so, it is a very awkward way to deal with a common RPG concept.

The first regular chapter of the novel is an in media res description of a desperate battle for the focus party, but this novel does not reach that battle by its end. This side story is planned for nine chapters and this novel only presents the first three, so presumably that scene refers to something which happens in one of the next two novels. That and the appearance of a mysterious character who points the protagonist in a certain direction provide solid hooks for further novels. Ultimately this isn't a bad story as fantasy RPG adaptations go, but not much about it stands out, either.