『お前は人間だ。......僕についてこなくていい』
漆黒の髪と紅玉の瞳を持つ魔王と呼ばれる主は王城を去る時、そう言った。
さすが魔王、残酷だ。今更、戻れるわけもない。魔物達との生活も悪くない。あまりの考えなしに頭痛がすることがあるけれど、それは人間だって同じだ。
それにあなたはまだ人間だ。人間らしい幸せをつかめる日だってくるかもしれないのだ。
だからどうか、自分があなたの望みを叶えるから、人間に絶望しないで欲しい。
『土地が欲しい、だと? 魔王に売って欲しい? ああ、いいだろう』
でも思う。人間にしかなれない自分は、思ってしまう。
『その代わり金になる魔物を我々に差し出せ。魔王の信頼が厚いお前ならうまく間引けるだろう? できないなら土地は渡さん。狭い土地で魔物同士、せいぜい共食いでもすればいい。なんといっても魔王様は人間と争わないのだからな』
一度きりで終わるはずだった。自分が一度だけ手を汚せばすむ。そう思っていた。
まだ幼かった自分は、一度ついた汚れは落ちないと、そんなことも分からずに。
『この値段で売ると契約書でも交わしたか? いいじゃないか、また魔物を売ればいい』
『あの土地を取り上げられたくないだろう。魔物達がまた棲む場所をなくしてしまう』
『騙した? 人聞きの悪い。魔王を裏切っているのはお前じゃないか』
――こんな世界なら、あなたはいっそ、魔物であった方が幸せではないかと。
いつだって自分はそう思ってしまうのだ。人間らしく。
「あら、お目覚めになりまして? キース様」
ぼんやり目を覚ましたキースは、寝台の脇に腰掛けてこちらを見下ろしている人物に気づいた。カーテンの隙間から差し込む朝日を背にしており、顔がよく見えない。だがその鈴の鳴るような上品な声と、日の光に煙る金の髪には覚えがある。
問題はここが自分の部屋で、どうして彼女が、ということだろうか。
「......アイリーン様。夜這いならぬ、朝這いとは――っ」
とりあえず上半身を起こそうとしたら、首元に刃物が光った。目だけを素早く動かすと、ベルゼビュートが寝台脇で腰を低くして気配もなく潜んでいた。
「ベルゼビュート。ここ第五層ですよ。どうして結界の外に出てるんです?」
「今の俺はアイリーンの忠犬だ」
「騎士以下になってますが、それでいいんですか」
「それがクロード様のためだと言われた」
その回答に、内心で自嘲した。
(これは、横領からバレましたかね? まあ大人しく見すごしていたなんて、不審がられてもしょうがないですけど)
しかも先手を取られた。彼女は賢い。勘も良いし、度胸もある。どう口車にのせたのか、ベルゼビュートも丸め込んできた。
しかし何をどこまで、どれだけ知られたのか。証拠はそうそうつかめないはずだ。
「ねえキース様。あなた、悪いことなさってるでしょう。クロード様に黙って」
キースは黙ったままいつもの笑顔を保った。同じ人間の少女は、唇を歪めて笑いかける。
「わたくしも仲間に入れて下さいません?」
「は?」
意外な申し出に眉をひそめる。と同時に、鼻先にぴらりと書類を垂れ下げられた。
ぎょっと目を剥く。首元に突き付けられている剣のことも忘れて飛び起きようとしたが、ひょいとその紙は持ち上げられてしまった。
「い、いいい一体、それをどうやって手に入れたんです!?」
「ふふふ、キース様。あなたの唯一の弱点は、人間側に味方がいないことですわね。――いいことを教えて差し上げますわ。あなたは頭がいいから分かるでしょう。恐らく近いうちに、聖剣の乙女が目覚めます。リリア様よ」
どうしてそんなことが分かるという疑問と一緒に、一気に頭の中にその後の展開が思い浮かんだ。
「......聖剣があれば魔王ですら敵ではない。クロード様の命が狙われる。だが聖剣は魔物にしか――人間のままのクロード様にはきかない。クロード様を竜に変えてしまうために、何か仕掛けてくる......? ああ、そう言ってベルゼビュートさんを丸め込んだわけですか」
「大正解。さすがね。廃城の中で誰より世情をよく分かっているのではなくて?」
「高官ですからね。......ただ、これは本当に聖剣の乙女が目覚めるならの話ですが?」
「そこは信じてもらうしかないわ。そのうえで問題よ。言い伝えによれば、魔王――クロード様は怒りや憎しみや人間への負の感情を抱えきれなくなった時、本来の魔物の姿、すなわち竜に変化し、本当に魔物になってしまう。だったら人間は何をすると思って?」
「......魔物を売る、とかですかね? 魔物を苦しめればあの方は人間を憎む」
わざとかまをかけてみた。するとアイリーンは目を丸くしたあと、小さく笑う。
「だからあなたはこんなに頭が回るのに、ゲームでいいように使われて死んだのね」
「は? ゲーム?」
「こっちの話よ、気にしないで。あなたの回答は半分正解、半分間違い。正解はこう。あなたの裏切りを見せつけ、殺させる。そうすればクロード様は人間に絶望するでしょう。唯一信じていた人間に裏切られ、しかも自分が殺すんですもの。当然ですわね」
指摘されて、大きく目を見開いた。そうだ、基本的に結界の中にいて守られている魔物より、自分の方がよほど狙いやすく、使いやすい。
「さっきも言ったわ。あなたの弱点は唯一、人間の味方がいないこと」
寝台から立ち上がり、アイリーン・ローレン・ドートリシュが振り向く。
「だから、わたくしを味方になさい?」
そう言って、彼女は裏切り者に微笑んだ。
{You're a human.......You don't have to come with me} 
The King who was being called the Demon King who possessed the jet black hair and ruby eyes, said that to me when he was about to leave the Imperial Castle.
As expected from the Demon King; he was ruthless. It was even too late to turn back at this point. The livelihood with the monsters was also not too bad. I didn't have to think much. There were things that caused a headache, but that was the same for every human after all.
Besides, you are still a human. It is still possible that maybe one day you'll get to experience what is happiness as a human.
Therefore, please, since I'll be granting you your wish, I don't want you to lose hope towards humans.
{You said you want a land?You want me to sell it to the Demon King?Okay, I'll agree to it} 
But when I think about it. The 'me' that was only a human, ended up thinking about it.
{In exchange for that, give the monsters that are valuable to us. I think as someone whose the Demon King deeply trusts, surely you can select ones that would fit the bill perfectly. If you can't, then I won't give you the plot of land. Those monsters can engage in cannibalism in that small plot of land for all I care. Because in the end, that Demon King-sama can't be at dispute with the humans} 
It was supposed to end after just that one time. It was supposed to be done after I dirtied my hands only that one time. That's what I thought.
The still immature me, who didn't understand that once you were stained by such filth, it could no longer be removed.
{Can you exchange it with the contract if you were to sell them at this price?Isn't it fine? You can sell the monsters again} 
{You don't want that plot of land to be taken away, do you? The monsters' place to live will end up gone once again} 
{I tricked you? How scandalous. You're the one who betrayed Demon King, aren't you?} 
----In such a world, one would be happier if they were to live as a monster.
I always ended up thinking something like that. It was such a human thing.
[Are you awake now?Keith-sama] 
Keith, who was being absentminded after just waking up, realized that there was someone sitting by the side of his bed while looking down on his lying figure. Since the morning light shone through the gap of the curtain behind that someone's back, he couldn't see her face properly. But, he remembered that elegant voice that sounded like a bell and that ash blonde hair in the light of the day.
The problem was this is my room, why is she... is it for that kind of thing?
[......Irene-sama. You shouldn't do night crawling (1), and even more a morning crawl----] 
When he tried to rise half of his upper body right away, an edged tool shone on his neck. When Keith promptly s.h.i.+fted his gaze, Beelzebub, whose presence was concealed was crouching by his bedside.
[Beelzebub. This is the fifth layer, you know? Why are you outside of the barrier?] (Keith)
[I am currently Irene's loyal dog] (Beelzebub)
[You've become less than a knight, is that okay with you?] (Keith)
[I was told that it's for Claude-sama's sake] (Beelzebub)
At that reply, self-deprecation rose at his inmost heart.
(I wonder if the matter about the embezzlement has been exposed? Well, there were things that I quietly overlooked, so it can't be helped if they have distrust upon me)
Moreover, it was something that he took the initiative of doing. Irene was smart. Her intuition was excellent, and she also had guts. Whatever it was that she had cajoled, she was able to coax even Beelzebub into doing it.
However, what, how much, and to what extent did she able to find out? She shouldn't be able to get a hold of that much evidence.
[Hey, Keith-sama. You're doing something bad, aren't you? And you keep it hidden from Claude-sama] (Irene)
While maintaining his silence, Keith kept on smiling. Irene who was a fellow human curved her lips and smiled at him.
[Can you include me into that circle of friends of yours as well?] (Irene)
[Huh?] (Keith)
Keith knitted his eyebrows at her unexpected proposal. And at the same time, she dangled a doc.u.ment in front of him.
Startled, Keith's eyes widened in surprise. He seemed to forget about the sword that was on his neck when he tried to jump on his feet, but Irene swiftly lifted up the paper.
[H, h-h-how on earth did you get that!?] (Keith)
[Fufufu, Keith-sama. Your only weakness is you don't have an ally from the human side. ----Let me tell you something good. You're intelligent, so you should be able to understand, right? Perhaps before long, the Maiden of the Holy Sword will awaken. Lilisama that is] (Irene)
Just as he was about to question how she knew of such thing, immediately a development of what's going to happen next came into his mind.
[......If there's a Holy Sword, then even the Demon King is no match for it. Claude-sama's life will be targeted. But, the Holy Sword can only hurt the monsters----it will not be effective as long as Claude-sama is a human. If Claude-sama were to transform into a dragon, something must've triggered it......?Ah, having said that, is that why you coaxed Beelzebub-san into something like this?] (Keith)
[Spot on. As expected. In the abandoned castle, who else other than you who can understand the human's nature so well?] (Irene)
[That is because I am a high ranking official after all. ......However, is this truly a what-if conversation about the awakening of the Maiden of the Holy Sword?] (Keith)
[You have no choice but to believe it as that. In addition to that, here's a question for you. According to the legend, the Demon King----Claude-sama, when he can't hold down his negative human emotions such as anger and hatred, he will truly become a monster by transforming into his monster form that is a dragon. Then, what do you think humans should do?] (Irene)
[......Things such as selling the monsters?If the monsters were to be inflicted with pain, that person will come to detest humans] (Keith)
He purposely asked a leading question. After Irene stared at him in wonder, she let out a burst of small laughter.
[You have such a brilliant mind. You used it this well in the game as well and ended up dying] 
[Huh? Game?] 
[Nothing. Don't worry about it. Your answer is half correct and half wrong. The correct answer is to let your betrayal be known and get killed for it. If you do that, Claude-sama will surely feel despair over humans. The only human he ever trusts betrayed him, and he ends up killing that person himself. So, it's a natural course of action] (Irene)
When Irene pointed that out, his eyes widened. That's right. Basically, more than the protected monsters inside the barrier, Keith himself is an extremely easy target and can be easily used.
[I told you just now. Your only weakness is you don't have an ally from the human side] (Irene)
Standing up from the couch, Irene Lauren D'Autriche turned her face towards him.
[That's why... will you be my ally?] (Irene)
As she said that, she smiled at the traitor.
Villainous Daughter Aims for the Last Boss
悪役令嬢なのでラスボスを飼ってみました
https://www.novelupdates.com/series/villainous-daughter-aims-for-the-last-boss/
Drama Fantasy Romance School Life Shoujo
Adapted to Anime Adapted to Manga Aristocracy Beautiful Female Lead Bloodlines Broken Engagement Business Management Businessmen Calm Protagonist Demon Lord Demons Female Protagonist Handsome Male Lead Hated Protagonist Kuudere Multiple Reincarnated Individuals Nobles Otome Game Politics Reincarnated in a Game World Royalty Saints Sword And Magic Villainess Noble Girls
https://ncode.syosetu.com/n2766dz/
永瀬さらさ