Isekai Tensei!: Akuyaku Ouji wa Goei Kishi ni Dekiai Sareru!!

The people wish for the execution of the royal family! After being involved in a traffic accident on the way to school, he died, having never truly lived. When he opened his eyes again, he found himself reincarnated into the world of the novel, "The Tale of the Kingdom of Dawn," where men can marry and even bear children. Not only that, he's now in the body of the 6-year-old Prince Arkfeld, the future villain who's destined to be executed by his former fiancé?! Surrounded by his doting guardian knight and equally doting older brothers, Arkfeld resolves to change his fate. He's determined to rewrite the story and claim his happy ending! (Source: MangaPlaza) Note: Includes two extra chapters.