Dukedom's Legendary Prodigy summary:
Summoned into another world, Han Sung worked his entire life as the empire’s SSS-class monster hunter. After countless struggles, he lost his life and came back as the first-born son of the Jackson Duchy, ‘Dale’. He was the continent’s greatest dark magician and the leader of the dark tower, The Black Duke’s son. ‘I will destroy the empire with my own hands.’ Swords, magic, and the art of strategy. With his previous life’s knowledge and intelligence as his background, Dale is reborn as the genius of the duchy. Just how far will his abilities go? His adventure starts now without an inkling of hesitation!