Bernardo de Corleone. Sicilian, right? Correct. Must be one bad dude, right? Correct. Especially if he had aliases like Filippo Latino, Philipi Latini, and Knuckles Cardozzo. (Okay, I made the last one up.) He was the son of a shoemaker, but Spanish troops occupying Sicily thought it would be entertaining to teach the kid to handle a sword. He became the protector of his small town, and then the best swordsman in all Sicily. Sure, I'm thinking The Godfather, but with the exception of Michael Corleone's futile attempt to save the Pope in the farce that was Part III, I don't see much connection between the Corleones and the saints.
After Bernardo killed a man in a duel, he sought sanctuary in a Capuchin friars' church. But really, it is Sicily; who hasn't killed someone and hidden in a church at one time or another? The difference for Filippo, err, Bernardo, is that he reflected on the emptiness of his life and experienced a spiritual conversion.
He was very tough on himself, which is why someone should probably not set his own penances anymore than he should represent himself in court or perform dentistry on himself, but he was very kind to animals. Neighbors from the whole region would bring sick animals to him, and his prayers were said to cure them. Michael might have been tight with the Vatican brass but I didn't see him cure anything. At least Fredo could make the fish take the bait with his prayers, until he became fishbait himself, that is.