The System Conceals the Fact That I Am an Invincible Boss

I'm sorry for hiding it from you for so many years, but you are actually very strong. After I chopped down an ugly monster, the system said in my head. "What the hell? Did I level up by killing monsters?" Um, no, don't be angry. In fact, you have always been quite strong. "What!" What I mean is, actually when you come to this world, you must be invincible... "??? System, give it to me!" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.