Isekai Ommitsu Boken Ki 3 [Light Novel]

[Machine Translation] Mikage Kuroto is a high school student who suddenly wandered into another world. Making full use of his powerful cheat ability, the "Hidden Man," he saves the town from a calamity-class ice dragon created by demons and is called the "Hero of Pure Blackness" by the people. From a plan left behind by the demons, he discovers that an all-out attack on mankind is imminent, and sets out for the royal capital of the Kingdom of Colorvoice to call for preparations for the attack. However, the royal castle has already fallen into the hands of the demons, and the capital is threatened from both inside and outside. As cities around the world fall one after another to the demons' massive offensive, Kuroto mobilizes all the adventurers to execute a defense strategy to protect the royal capital, the last stronghold of mankind!

突然異世界に迷い込んだ高校生、御影黒斗。強力無比なチート能力“隠密者”を駆使する彼は、魔人が生み出した災厄級の氷竜から町を救い、人々から「純黒の英雄」と呼ばれるようになっていた。魔人が残した計画書から、人類への総攻撃が迫っていることを突き止めた彼は、襲撃への備えを呼びかけるためにカラーヴォイス王国の王都を目指す。しかし、王城はすでに魔人の手に落ちており、王都は内と外両面からの脅威に晒されていた。魔人の大攻勢により各国の都市が次々と陥落していく中、人類最後の砦である王都を守るべく、クロトは全冒険者を動員した王都防衛作戦を実行に移す!