Billy the Kid. His real name is William Henry McCarty Junior.
A representative outlaw from the American Wild West, even in modern times his popularity is extremely high.
From the fact that one of his few remaining pictures was put for a price of two hundred million yen in an auction, one can perceive said popularity.
His father is unknown, but it seems that he received a higher education from his mother and, considering he was a Western outlaw, he left behind some skillfully written letters.