High School DxD: The Lucifer's Devil Trigger

Transmigrating into the perilous world of High School DxD is dangerous enough, but waking up as Levi Lucifer—the notoriously weak, pure-blooded descendant of the original Demon King—is a death sentence. Surrounded by the hostile Reformist Faction and living under the shadow of his mad, Transcendent-class grandfather Rizevim, Levi's future seems bleak. His half-brother Vali has already fled, leaving Levi as the sole heir to a crumbling legacy and a prime target for assassination. Everything changes when Levi awakens a mysterious check-in system. By interacting with key figures of destiny, he begins to unlock unimaginable powers from across the multiverse. Armed with Vergil's legendary Yamato blade, the unstoppable Devil Trigger, and Observation Haki, Levi secretly builds his strength while playing the fool. He refuses to be a pawn in the Underworld's political games, choosing instead to forge his own path by gathering a peerage of unparalleled power. From recruiting the Silver-Haired Slayer Grayfia and the tragic Nekomata sisters, to crashing a Holy Grail War in Fuyuki City to claim the Third Magic for infinite mana, Levi's ambitions know no bounds. With legendary Heroic Spirits, Dragon Kings, and even the Infinite Dragon God Ophis drawn to his side, Levi Lucifer is ready to tear down the old order. The Underworld is about to learn what happens when the weakest devil stops holding back and claims his rightful throne.