The Fallen hero

You are born in the world where magic and monsters exist. You been an F rank hero for 5 years (The lowest rank in the hero association) but still can't level up that's why they called you " The Fallen Hero" or "The lowest". You are frustrated from they're bullies so you decide to training up in the forest. After 100 years of training your skills, magic, intelligence, power, strength and all human abilities is maximize but your level is still 1. You decide to give up and go home and when you got home you see the bullies and they talk to you.