Shinimodori no Reigai Ouji ga Kenou to Yobareru made: Michibiita no wa Bukiyou na Koushaku Reijou no Inori deshita

Dietrich, nicknamed the "Cold-Disaster Prince" because he seems incapable of warmth, became king at 17 under his ambitious mother's influence. But life turns tragically cruel: his younger brother Oscar seizes the throne, then he is publicly executed. Miraculously, at the very moment of his beheading, Dietrich's consciousness returns to four years earlier, when he was 13. With that memory, he resolves to right his mistakes: this time he will cherish his fiancée, Marguerite. In his previous life, he pushed her away with coldness, even though she stayed loyal and kind until the end, praying for him. Now, knowing what he lost, he vows to do everything differently. Thus begins his revenge, his path to being called the "Wise King."

(Source: Akita Shoten, translated)