It was just after I finished accepting the request to procure supplies and sent Sylvia out the front door of the store.

　Alexia came up the slope with great enthusiasm, taking the place of Sylvia who was returning to town.

'Hello, Luke-kun!　I'm here to tell you that our work is finally coming to a close!
That's good. You think you can handle the noir?
Of course. I'm not going to run off just because I'm done. Noir should be coming over here later.

　The job that had been left to Alexia and Noir, namely the development of a winter gear that would help the knights of the north, as requested by Oswald of the Ash Eagle Order.

　I had asked them to make a prototype from each approach, a craft and a magic tool, and I heard that they had already achieved a certain amount of success.

''What on earth did you make?''
'Here's a prototype. I'll tell you more about it when Noir gets here.

　Alexia smiled proudly as she showed him the palm-sized parcel.

　A short while later, Noir also came towards the shop, so she decided to take it back to the room where she had been talking with Sylvia earlier to hear the report.

　The 'prototypes' that the two of them brought with them were both small enough to fit in a package that was big enough to fit in their hands, and they seemed to be easy to tuck away in their pockets.

''It's surprisingly small, isn't it?''

　When I told her frankly what I thought of, Alexia fished up the edges of her mouth as if she was on her own terms.

"Based on the information I received, the two of us discussed it, and we decided that if we wanted to satisfy the conditions we were presented with in the most efficient way, it would be best to create a 'heat source that has sufficient temperature and can last for a long time' in a size that can be easily carried around.

　Indeed, if we integrated the required specifications of the Ash Hawk Knights as it is, it would be exactly what Alexia said.

''But isn't it too small for that?　What I was imagining was a lantern-sized, fireplace-like tool.
''The source of the idea is the warm stone that Sakura mentioned. The Knights of the North have already taken sufficient measures, and if they are still lacking, I thought it would be good to be able to warm up the cold areas in a concentrated and flexible manner.

　That's why we focused on small size and light weight.
　It's not necessary to warm your entire body with one tool, and that's why they put emphasis on reinforcing the areas where the current measures are insufficient.

　Alexia finished explaining the overall design policy and urged Noir to start with a separate explanation from that.

''Well then, ...... me, first. This is ...... a ...... prototype that I made, using only ...... magic tools, ......

　What Noir took out of the wrapping was a square-shaped, flat sachet, not much bigger than the exterior wrapping.

　The four sides were tightly sewn together, and it could be seen at a glance that it wasn't intended to take out the contents.

''Nah, the contents are ...... such ...... style ......''

　This time, a sachet with one of its four sides unstitched was taken out and its contents were spread out on the table.

　Inside was a bundle of papers, slightly smaller than the outer bag.

　All of them had magical patterns drawn on them, but upon closer inspection, it seems there were two different patterns, and they were stacked on top of each other.

''Could this be a heating spell?''
"...... Oh, oh, ...... there's a lot of stuff, and there's ...... a lot of ingenuity. ......

　In his usual faltering tone, Noir began to recount, somewhat happily, the story of how the prototype came to be in its current form.

　I started out with a simple idea of carrying a heating spell, a warming spell, but there were two major problems.

　One is that it's physically just a piece of paper, so it's a hassle to carry it around so it doesn't get soggy.

　And the other was that the spellbook size had fundamental performance limitations.

　If I set the output to a point where the part I touched felt hot enough, it would quickly reach its limit and disintegrate, and conversely, if I reduced the output to make it last longer, this time I wouldn't feel any warmth at all.

　With this in mind, the next time I tried bundling multiple spells together, or folding a larger one, but this time I had another problem.

　The closely folded spells caused them to ignite and burn up every once in a while, probably due to the magical effects and the extreme concentration of heat generated.

　As expected, the danger of spontaneous combustion ants wouldn't be a viable product.
　The reason why the prototype Spellscroll 'cannot be used unless the scroll is opened' is also to avoid such accidents.

　However, Noir did not want to abandon this approach.

　After thinking of a countermeasure, he came up with the idea of putting a control spell between several bundles of heating spells to prevent spontaneous combustion.

'A, of an idea, the original ...... Sylvia is cooking, when ...... hot, pots and pans...' ...of a potsherd, on top, because I saw it on ......, right? ......

　The inconvenience of high heat propagation is prevented by putting something in between.

　The principle itself became a completely different thing than a potsherd, but the structure to prevent spontaneous combustion was born from such an everyday sight.

　The last remaining problem was that, just as a spent spell scroll would disintegrate and turn to dust, this prototype would turn to dust once its heating time was over.

　It was inconvenient to put in a pocket or pocketbook, but the solution to this was very simple, and as soon as he started thinking about it, he settled on 'just put it in a bag'.

'Try it ...... and see, give me ....... Let the magic, flow, if ...... fever, do ...... to .......
You mean like this?　...... Ooh, sure.

　You can feel the heat gently flowing through the fabric of the sachet.

　Only the part that you touch directly gets warm, and if you let go of it, it doesn't get warm at all, but it's perfect for holding in your hand or carrying in your pocket.

　Most importantly, it's smaller and lighter than you might imagine.
　It's small enough to fit in your pocket and explore a dungeon without it bothering you at all.

'...... na, what ...... improvements, or is there ...... likely, or ......?'
''If I had to say something stronger, I might worry about the firmness when I bend it because the contents are a bunch of paper. Isn't it a little stiff, or maybe ...... spells can be made out of cloth too?

　As soon as I casually said that, Noir looked up with a huff and his eyes lit up and he replied with a heartfelt and lively look.

'Yeah, yeah ......!　Normally, there is no advantage, because ...... doesn't, but ...... cloth can also ...... to scroll, material... ...!　Next time, let's make a ...... prototype with it ...... and try ......!