Tensei shita Saki wa Jigoku deshita: Sanbyakunen Tsuzuku Henkyouhaku-ke no Bouei SensenNewReborn Into Hell, the Place Where He Was Reincarnated Was Hell; 三百年続く辺境伯家の防衛戦線; 転生した先は地獄でした――三百年続く辺境伯家の防衛戦線

Victor Vangard, who reincarnated into a noble family, started a wealthy second life—or so it should have been. Until one day, at the age of eight, his father took him to face the battlefield. What he witnessed there was "Eclipse," monstrous aberrations that trampled soldiers with overwhelming numbers and power. In truth, the Vangard family has been fighting for three hundred years to annihilate the continuously emerging Eclipse! In a hell where neither fleeing nor refusing is allowed, what will Victor seize, and how will he survive? A super Hard Mode Isekai tale, colored by fate and despair, grandly begins!!