Master of Ragnarok & Blesser of Einherjar (Manga) Volume 3

Strategy versus power: The showdown with Steinorr and the Lightning Clan approaches!Yuuto has finally come clean with Linnea about why he can't marry her. But just as it seems they've reached an understanding, troubling new information arrives: The Lightning Clan is preparing to launch an invasion! Steinrr's army is fierce, and the man himself possesses monstrous inhuman strength. Yuuto has reliable allies like Sigrn and Skvir, and he has his 'cheats' - tactics and technology he copied from future history. But will that be enough for the Wolf Clan to prevail against a foe said to be invincible?