I Became the First Prince: Legend of Sword's Song

"I was reincarnated as a sword and lived for hundreds of years, spending my entire existence cleaning up after others. Then, out of nowhere, I ended up taking over the body of the fifteen-year-old First Prince—a notorious good-for-nothing. “How many do you think I’ve raised?\" The great knight once called invincible, the Dragon Slayer who brought down the Mad Dragon, the Mercenary King... I raised every last one of them. The magic sword Gruhorn, possessing the body of the rogue First Prince... this is the myth he begins to write anew. "