After being betrayed and killed by his best friend, Tsuoma Sadeo is reincarnated into a fantasy world where humans and magical creatures coexist. Armed with his indestructible sword and immense magical powers, he becomes a formidable sword mage. However, his new life takes an unexpected turn when he is met by the Princess of Straterfall Kingdom, his summoner, who has a crucial mission for him. A powerful demon, Urea, has possessed the Empress of Latasha, the second most powerful kingdom, and is secretly rallying dark mages to awaken the King of Demons, Agarrat, from the abyss. A goddess, determined to prevent this catastrophe, forms an unlikely alliance with the Princess of Straterfall. Together, they summon Tsuoma and, by mistake, his friend Teruki. The two must undergo rigorous training to defeat the Three High Demons: Urea, Trezona, and Duggan. As the stakes grow higher, Tsuoma and Teruki race against time to prepare for the ultimate battle. Will their training be enough to save the world from destruction, or will they run out of time? And who exactly is the supreme one and what is his or her plan?
A small unnoticeable crack appeared in the sky and gradually expanded. The little crack began sucking out the mana of everyone gradually. No one noticed this. It was the beginning of the calamity.
