「大雑把だけど、この階は四つのエリアに分けることにした」
「えりあでございますか？」

　十階をちょうど真ん中で二分する湖までは、徒歩で約一時間.
　だいたい五キロほどの距離だろうか.
　たっぷり時間があるため、向かいがてらこの一週間で調べた結果をパウラに説明していく.

「まず、一つ目は――」

　振り返りながら、俺は背後に広がる壁を持ち上げた手で指し示す.
　視界の左右に広がっていく絶壁の高さはおそらく百メートルを超え、幅も十キロはあるだろう.
　あちこちに大きな岩が顔を出し、その周りを淡いピンク色の草が彩っているのが見える.

「南の壁周辺だな. 主な魔物は曲角羊だけで、比較的安全な場所だよ」

　階段を下りてすぐの壁は非戦闘的な曲角羊の生息地であり、また睡眠薬の材料となる夢見草と、昆虫系の魔物を寄せ付けない虫除け花が採取可能である.
　ただ虫除け花に関しては階段の周囲には自生していないため、出入りする際に襲われる危険性があるので注意だ.

　曲角羊は基本的に岩伝いに崖を移動して、夢見草をむしゃむしゃ食べているだけの大人しい魔物である.
　ただし同胞が襲われていると、助けに入る性質がある点だけは気をつけなければならない.
　もっともこれを利用して、数頭まとめて壁から引っ張り下ろすこともできるが.

　特技は角を突き出して走ってくる<突進>と、周囲の生物を眠らせる<眠りの吐息>.
　後者はとても危険であるが、顔を攻撃していると出しにくいようである.

「なんといっても素晴らしいのは、羊毛と肉がたっぷり取れるところだな」

　百頭近い羊が勝手に放牧されているのだと考えると、笑いが止まらなくなってしまう.
　しかも適当に間引いても、次の日には元通りの数になるのだ.
　もうこの発見だけで、十階まで来てよかったと思えるほどである.

「それにまだ試せていないが、もっと美味しい活用法もありそうだしな」
「そうなのですか？」
「ああ、帰り際にぜひやってもらうつもりだよ」
「はい、なんでもお言いつけ下さいませ」
「で、二つ目のエリアだが――」

　今度は視界の両側に立ちはだかる壁を、左右に伸ばした俺の手が指し示す.

「西と東の壁の辺りだな. こっちに住んでいるのは大目玉蛾. 日が暮れたら、絶対に近づきたくない場所だな」

　両壁の周辺には灌木が何本も生えており、ちょっとした林のようになっている.
　大目玉蛾どもは、昼間はその木々の暗がりに潜んでおり姿を見せようとしない.
　ただし太陽岩の輝きが弱まる夕暮れ時になると、棲家を離れ活発に飛び回りだすのだ.

　何度か日没時まで居残って調べた結果だが、どうやら光に反応するらしく、到着した初日に俺たちが襲われたのも妖精の翅が光っていたせいらしい.
　体長は三十センチほどで、翅には毒々しい目玉模様がついている.

　特技は羽をひらひらさせて意識を混乱させる<まどわす>と、厄介な鱗粉をばらまいてくる<目潰し粉>だ.
　こいつらは物理的な攻撃力はほぼないのだが、集団で襲ってくるので侮れない相手である.

　検証用に白照石のランタンをもたせた骨子ちゃんを少し歩かせてみたのだが、たちまち集まってきた蛾にありとあらゆる箇所が覆われてしまう有り様となった.
　これが生身の人間だったら、間違いなく窒息しているだろう.
　骨子ちゃんで実験してよかったとは思えたが、そのままこっちへも戻ってきそうになった時は、生理的に無理すぎて非常に後悔した体験でもあった.

"Yeah, yeah, that was scary. ......
Yeah, it was bad.
Yeah, I would have liked to have seen that.
No, I wouldn't recommend it. I don't recommend it, seriously.
Yeah, yeah!　I had a dream about it and it was awful!

　But Etan, Yoru and Kuu were fine, so it may not resonate with people who don't have the sensibility of ordinary people.
　As Mia and I were talking in unison, Paula looked like she wanted to say something for a moment, but when she noticed my gaze, she smiled her usual mysterious smile.

There was nothing in the east-west wall area that I could collect. It's too dangerous to linger there.

　Even though they stay still during the day, it doesn't mean they won't attack us.
　We can collect moth scales from the big-eyed moths, from which we can refine a dark potion, but I really don't think it's worth the trouble to go and get it.
　I think the east and west walls should be inaccessible areas.

Thirdly, this place on the south side where we are walking now.

　At my words, Paula cast a curious glance around.
　The ground is mostly flat, with a few ups and downs, and nothing but sparse undergrowth and a few angular rocks to sit on.
　Yes, there is nothing here.

Oh, that's too bad.
I've walked all over the place, tried to touch it.

　On the south side of the lake, there was nothing but the same scene as far as the eye could see.
　The south side of the lake was just a series of similar sights as far as the eye could see.

And finally, the area on the other side of the lake, to the north.

　This is the area to the north, separated by the central lake. 　
　It's a hilly area lined with large trees, and it's an area we haven't reached yet.
　The far-sighted Etan said he could see several black and yellow striped things flying around.
　............ is a demon that I can somewhat imagine.

Should we count this lake as part of the area?

　The other side of the lake is about five hundred meters away.
　On the east side, there is a river that flows into the lake, and its upper stream leads to a hole under the wall.
　On the other side, on the west side, there was a river that flowed out of the lake, so that the water would not overflow.

　The river on the west side was divided into several tributaries, all of which flowed into the hole in the wall as a matter of course.
　It is truly a wonder where that much water disappears to.

　In the sky above the lake, I can see the figures of demons that repeatedly stop and move in small increments.
　They are much taller than I am.
　They're a swarm of sword-tailed dragonflies with abdomens that look like swords.

　They are so blind that they will attack you just when you are within 30 or 40 steps of the shore of the lake.
　They attack either by flying silently from above, grabbing their prey and ripping them apart with their sharp jaws, or by swinging their long sword-like abdomens and grabbing the severed parts and carrying them away.

　Its specialties are slashing with its vicious abdomen and noise waves that it emits by shaking its translucent wings.
　These wings are extremely tough, yet highly transparent, just like tempered glass.
　Although this wing is the only drop item, it seems to be a very useful material.



Well, I didn't come here to beat you today.

　The purpose of today was to build a bridge to survey the area north of the fourth.