[Baku Ado] Umareta Chokugo kara Saikyou Akuryou to Nounai Battle Shitetara Maryokuryou ga Sokutei Kanou Iki wo Koetemashita: Akutsuki no Ko no Kenkyo na Hadou

A frantic mental duel against the strongest evil spirit, waged just seconds after being born, somehow leaves his magic power completely maxed out. Kai Shirakami is reincarnated into an alternate Japan where creatures called Spirit Fiends roam. At his birth he is dragged into a ritual meant to summon the most powerful evil spirit; a curse strikes at his mother, and the raging spirit tries to seize Kai's body. While he battles it endlessly inside his own head, he unknowingly grows into an entity of staggering strength.