The Bastard of Swordborne

Story

Theo Ragnar, the 31st son of the mighty Grand Duke of Ragnar, was born without the legendary Ragnar Gift—a fatal flaw in a family where might is right. Labeled the “Ragnar Defect,” he and his mother were betrayed, meeting a brutal end at the hands of those they trusted. But death was only the beginning. Reborn at 17, Theo awakens not only with the Ragnar Gift, but with powers far beyond imagination. Fueled by vengeance and a second chance, he sets out to claim the glory he was once denied.

Synopsis via AniList (English).