The Third Prince of the Fallen Kingdom has Regressed

From the stuido that brought you Moon-Shadow Sword Emperor and The Legendary Hero is an Academy Honors Student.] Yuri, the unruly third prince of the fallen Briol Kingdom. After meeting his end while wandering in guilt, he ended up regressing to the spring of his 13th year, before the Empire's invasion began! "Briols do not abandon honor, even in death." One harrowing regret is enough. The kingdom shall be saved from ruin!