The Regressed Assassin

(DO NOT READ, i js didn't want to delete my first novel)

Liev was an arrogant, lavish, and useless son of one of the strongest awakened. One day, Liev got kidnapped by an unknown organization and suffered greatly. It's been a year since Liev was kidnapped and his family didn't come to save him, when Liev finally got out he spent 8 years of his life to get his revenge. As Liev was investigating, he discovered that it was all a misunderstanding. [Congratulations! You are chosen as a "character"] A floating screen appeared in front of him. He was given a chance to return to the past and fix his mistakes. What would happen if an assassin have a system?