Badass is defined in one word: Caravaggio.
Son of a bitch was the most bitchin' painter around 1600, and he brawled his way around Italy. He was so badass, the Pope fucking pardoned him for killing some dude in a bar, just so he could come back to Rome (he had been on the run) and paint for some Renaissance-era mercenaries who happened to just love epic art. Damn, son. Damn.
Art student: Professor, who was the guy who painted multiple grotesque beheadings SO BEAUTIFULLY?
Art professor: You must be referring to Caravaggio. *does not try to hide gleam of admiration in eyes* Damn, he was a badass.