Rimuru Tempest is victorious following his climactic showdown with Demon Lord Clayman. With Diablo's aid, the war with the Falmuth Kingdom ends decisively in Rimuru's favor. Fueled by increased migration and the integration of Jura Forest, the nation of Tempest undergoes rapid growth.

Rimuru's victory shifts the balance of power, giving rise to a renewed period of peace—but whether that peace will last is another matter. Yuuki Kagurazaka and Kazalim are conspiring with the Harlequin Alliance to bring about Rimuru's downfall. Furthermore, the Western Holy Church continues its intolerant crusade against Rimuru and his non-human subordinates. Both allies and enemies engage in a battle of wits, carefully advancing their agendas without shattering the delicate status quo. But once the first domino inevitably falls, the race to supremacy begins.