The Ancestor of Beast Transformation

There was a man who had witnessed his whole family being massacred. There is one person who needs to learn not to lose himself on the road to revenge. There was a person who once had a happy family. There is one person, but now he can only be alone forever. Even though he can go back to the past and live happily with his family. But he also knew that he could never go back to the past. There was a person whose original wish came true, but his wish failed to come true. Until... That variable appears.