The Executed Strongest Military Magician Rebuilds His Country with the Elf Princess of a Defeated Country?

The magical nation of Ingressa came to dominate neighboring countries with the power of groundbreaking military magic. Supporting this dominance from behind the scenes was Hert Eisenheim, who rose to the rank of archmage at a young age. However, due to a scheme by the court magician who was jealous of his talent, Hert was executed as a war criminal – but when he woke up, he found himself summoned before a young girl. The girl's name was Iris Refrain, and she was the first princess of the elven kingdom that he had destroyed.