The Gelmed Empire suddenly declares war on the Kingdom of Lyferia. In the following conflict, the king is killed and the castle is occupied. To top it all off, the enemy’s Magimatic mages try to abduct Rem. Despite never wishing to fight in a war, Diablo wields his magical powers against his enemies, slaying the Gelmed soldiers. While he successfully rescues Rem, Lyferia is still in a position of inferiority. To turn the tables on the enemy, Diablo single-handedly launches a surprise attack. “I will now «Teleport» into Castle Grandiose and engage the enemy!” The decisive battle approaches! Sylvie’s secret is finally revealed! The Demon Lord Krebskulm departs from Faltra! And what of Noah and the escaped Order of Palace Knights...?! This is the thirteenth volume of the adventures of an earth-shakingly powerful Demon Lord (or at least someone who acts like one) taking on another world!