ある日通り魔に襲われて命を失った三上悟は、 天文学的確率で異世界へと転生する。 しかし生まれ変わった姿は、 なぜか最弱モンスターとして名高いスライムだった！ 「こんなん認められるかー！？」 とか言いつつも、 見知らぬ洞窟でお気楽スライムライフを満喫するが・・・。 天災級のドラゴン『暴風竜ヴェルドラ』と遭遇したことにより、 運命は大きく動き出す！ モンスター転生ファンタジー、ここに開幕！

37\-year\-old Satoru Mikami got a new lease on life when he was reincarnated into another world...as a slime named Rimuru Tempest. But with the help of his wits, his newfound powers, and a little luck, he's started building a cross\-species village of goblins, direwolves, and dwarves! Rimuru doesn't know it yet, but his arrival is bringing major changes to his new world...

TIMES ARE CHANGING FOR THE WORLD! After a furious battle with the orc lord, peace has once again returned to the Forest of Jura. Rimuru may be heading up the Great Forest of Jura Alliance, but he's most worried about finishing his town...until a visit from King Gazel Dwargo of the dwarves turns everything upside down! Not only that, but Rimuru is about to have a run\-in with Milim Nava, an exceptionally dangerous demon lord known as the "Destroyer." What's a slime to do?!

NO REST FOR A NATION\-BUILDING SLIME! Now that Rimuru's monster\-centric town has blossomed into a bona fide independent nation, it's time for his next build and maintain diplomatic relations with nearby countries! With a group of his trusty monster pals, Rimuru travels to the Beast Kingdom of Eurazania and the Dwarven Kingdom to meet with their respective heads of state and represent his domain as best as a slime possibly can. As if there wasn't already enough on Rimuru's mind, the otherworlder Shizu has been visiting him in his dreams, begging him to save her former students. Looks like that'll be another stop on this pliable pioneer's itinerary…

Despite Rimuru's absence, Tempest was as peaceful as always. Well, as peaceful as a monster town called "Tempest" could get, anyway. But that was only until they learned that a bunch of heavily armed humans were coming their way. To make matters worse, the Beast Kingdom of Eurazania has declared war on Milim, and Rimuru is nowhere to be found...!

A meeting of demonic minds! Newly minted demon lord Rimuru has received word of a special assembly of all ten demon lords known as the Walpurgis Council. It just so happens that the topic of this particular meeting is how to best punish Rimuru for assuming his new title without their permission. Fortunately, he's got friends in high places who are willing to vouch for his authenticity, and this council could be the perfect opportunity to get revenge on the demon lord Clayman for the violence he brought to Tempest. Is this blobby big shot cunning enough to kill two birds with one stone?

News of demon lord Clayman's defeat by Rimuru shakes the Holy Empire of Lubelius to its core, especially since the Chief Knight of their Holy Imperial Guard, Hinata Sakaguchi, had once attacked Rimuru not long ago. In an attempt to avoid total warfare at all costs, Hinata shoulders the blame for all the bloodshed and decides of her own accord to head for Tempest...!

It's festival time in Tempest, and this exuberant ectoplasm knows how to throw a party! After reconciling with Hinata and securing his title as demon lord, Rimuru's pulling out all the stops to hold a massive bash in his nation of monsters, along with a little help from his many friends and allies!

『転スラ』のすべてがこの一冊に! 各キャラクターの紹介はもちろん、 魔国連邦をはじめ各国紹介、スキル分析、世界地図などの詳細な情報が盛りだくさん。 ファン必見! 『転生したらスライムだった件』のすべてをまるっとこの一冊に。

AN EVENT OF MONSTROUS PROPORTIONS! The Tempest Founder's Festival is in full swing, with Rimuru and all the monsters under him keeping busy setting up the attractions. From live concerts to incredible feats of monster engineering (most notably, the massive dungeon), revelers are sure to have their minds blown. But all eyes are on the main event\-the First Tempest Battle Tournament\-and who should decide to participate but the Hero himself, Lightspeed Masayuki! What will come of his chance encounter with the demon lord Rimuru?