The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat

The goddess is formulating a plan to stop the Hero's rampage. After defeating the Demon Lord and saving the world, next he will use his power to destroy the world. The goddess has decided to summon the souls of professionals from other worlds and reincarnate them. She summons the soul of the world's finest special forces soldier who excels in combat and asks him to defeat the Hero, but--