Zense wa Kentei. Konjou Kuzu Ouji

He was called a Sword Emperor who lived for the sword and died by the sword. And his end was a tragedy. However, by strange coincidence, he was reincarnated as the third prince in a country. He was enjoying his lazy lifestyle away from swords and heroism. As a consequence, people began referring to him as Prince Trash. He never cared about his derogatory name until one day, he encounters someone who gets the wheel of fate to move in motion.

Source: Alpha Manga