''Let's hear about the rainbow scale knights next. As you might have guessed, you guys are also reporting on the 'Thousand Year Corridor of the Abyss', right?
Okay. Hild, can you do me a favor?
Yes, I'll take care of it.

　After receiving instructions from Commander Angelica, Hild stands up from his chair with materials in hand.

''We, the Rainbow Rainbow Rainbow Scales Knights, have been conducting research and analysis regarding the 'Ark of the Elements' and the first labyrinth of the relevant dungeon, the 'Thousand Year Corridor of the Abyss', and this morning we have finally gathered enough of an opinion to be able to report it.

　A crisp and clear voice comes out under the hood.

　As research is his primary role, he seems to be accustomed to such presentations.

I'm going to have to say that I'm not a fan of this kind of presentation. Sir Ambrose of the Order of the Sui-Gan's field research of the 'Thousand Year Corridor of the Abyss'. The information was sent to the Knights' own research facility in King's Landing for analysis and review from a magical perspective, resulting in .......

　As I thought, Ambrose had bitten off a piece, too.
　As far as he was concerned, it was probably an argument that he had provided the results of his personal investigation to the rainbow scales.

　However, the results of the analysis Hild told him were beyond the scope of his imagination to the extent that this minor surprise disappeared in an instant.

...... Perhaps the 'Millennium Corridor of the Abyss' is itself a huge defensive magic circle. It's an extremely large area of counter-(──)sky(──)protection that most ordinary cities could easily contain.
Is ......?
"Huh?

　I'm stunned, and His Majesty lets out an interestingly surprised voice.

　Each word that pops out of Hild's mouth inevitably doesn't connect with the image I know of "The Thousand Year Corridor of the Abyss" ...... and, by extension, the dungeon.

　A labyrinth buried under the ground is a magic circle of anti-aircraft defense?

　Rather than sorting through the information in his head, Hild adds a more detailed explanation.

'We didn't have a complete picture of the labyrinth in the material Mr. Algernon left behind, but by piecing together the fragmentary information, we were able to map out the majority of the structure.
"You have done a good job compiling my brother's miscellaneous data. At worst, I thought I should send the Falcon to use extrajudicial measures to have him use the [cartography].

　It's no wonder Duke Kingswell is so impressed.

　I've also checked the pile of materials brought into the White Wolf Knights' archives, but it was in such a state that it seemed as if there was no end in sight just to classify them by type.

''The principle itself is simple. There must have been a product in the magic tools handled in the White Wolf Store that uses mithril metal wires to construct magical patterns to produce a specific effect.
...... You don't mean to tell me that the mithril wall disguised as a labyrinthine stone wall worked the same way as that metal wire?
'Perhaps. I've made a scaled-down model of the structure to compensate for the unknown structure, and I've been informed that it functioned properly as a magic circle.

　Since there is a limit to the amount of mithril that can be handled, products that use mithril in large quantities have to be mostly made to order, but they certainly handle that kind of product as well.

　For example, the poacher-type magic power supply device (supplier) that is always on hand when the need for battle or large-scale [restoration] is assumed, was also structured so that the magic power extracted from the magic crystals stored in it was poured into the body via mithril metal wires.

'The labyrinth itself is a magic circle ...... defense against the ...... upwards, no way ......'

　I couldn't help but utter an imagination that popped into my head.

''A shield to protect the Ark of the Elements from the attacks of divine beasts?!

　Why was the labyrinth so vast?
　Why did they build the wall by throwing in Mithril so sparingly?

　The answer to both questions can be explained as a matter of necessity.

　The reason why the area of the labyrinth was so vast was because it was necessary to cover the entire area below the first level.

　The large amount of mithril was used because it was necessary to achieve the required strength and self-healing capabilities.

　The scenes of the far past that he had once glimpsed included a hellish scene of a beast that was too huge and extreme to be ruled over.

　If they were turning on humanity and even attacking the prototype of their underground dungeon, the Ark of the Elements, then preparation for an immense physical attack from above to below the ground must be essential.

"We have also come to the same hypothesis as Commander Luke. The reason why it is a hollow metal rainbow - not just a huge metal circuit - is because of the maintenance of the defense mechanism.
"So you also took into account the possibility that the auto-repair function couldn't handle it. Not only did the creator, Alfazul, have the foresight to do so, but the might of the gods and beasts that had to go that far was also tremendous.

　His Majesty the King nodded curiously as he stroked his beard.

　In the meantime, multiple known information combined in my head and an imagination that seemed impossible to imagine.

'Luke, you look like you've got an idea. Don't hesitate to let me hear it.
...... This is just my imagination. ......

　As urged by His Majesty, he put into words an idea he had just thought of and had no support for.

'The ...... 'Millennium Corridor of the Abyss' had a gimmick planted in it that opened a hidden passage in conjunction with the damage to the inner walls and unleashed the dragons of the first level. It was thought to be a defense mechanism against intruders, but to be honest, we felt that it was not a very efficient substitute.

　The discovery of that thing goes back to right after I started the White Wolf Store.

　When I escaped from the labyrinth and when I put it into practice in front of the Silverwing Knights to clear my suspicions of mithril trafficking - in conjunction with these two destructions, the dragons were unleashed and an unexpected battle was to take place on the fifth level of the Sundial Forest. It's a case we've forgotten.

　The theory that it was probably a defense against intruders was the most plausible, but there were some questions that could not be resolved.

　Because if someone sneaks into the labyrinth and destroys its inner walls, which in turn releases a dragon, the dragon cannot attack the intruder because it cannot enter the labyrinth due to its size.

It has been explained that dragons cannot attack intruders in the labyrinth, and that it is a bypassed defense that gives the impression that dragons will appear if you mess with the labyrinth. ...... "Unless The Thousand Year Corridor of the Abyss is a defense against divine beasts.

　It seems to me that the scale of my ideas has grown a notch or two.

　However, it was only natural to think of it this way.

''That gimmick must have been a mechanism to respond to the divine beasts that attacked across the surface of the earth to the point where they could shatter the earth and damaged the labyrinthine magic circle by sending a horde of dragons at them.

　Of course, we don't know if the divine beast could have managed to do something with the swarm of dragons.

　But the possibility must be that they were able to dismiss it as an initial response to loosen up their attacks.

'It's an interesting theory. Angelica, do you think it's worth considering?
'Yes, sir. We'd like to continue our analysis in that direction as well.

　A mere thought has been accepted by both the king and the leader of the knights in charge.

　The door to the reception room knocked behind me in bewilderment, and the chamberlain reported the visit of his most important guest.

''Senator of the Northern Tree Sea Federation, Lady Eir Sethlumnir has arrived.

　A sense of urgency filled the reception room.

　But His Majesty is the only one who remains unruffled, and replies to the attendant on the other side of the door.

"Let us in. "Let us pass through," he said, "and do so respectfully.