How I Became a Legendary Assassin

Alex's life wasn't very interesting, it was as normal as one could be. He was a typical office worker. He never found life very enjoyable, yet he kept living. One day while on his way home, Alex got into car crash and died. In his final moments he wished that if he got another chance his life would be more exciting. And his wish was heard, and granted. How will he live? What awaits him? Why will he become an assassin?