The word "baccano" is Italian for "ruckus."
Ryôgo Narita did not create a detailed storyline, but instead focused on the characters and how they would interact and impact on the original plot/storylines. Although he allowed the characters to "move how they want", he found it troublesome since some characters were hard to move along with the plot and other characters "moved too much, leaving the plot in ruins."
According to Ryôgo Narita, the main protagonist of the whole saga is Firo Prochainezo. Narita however found him a plain character and had difficulty giving him a suitable storyline within the saga; he solved the problem once he had Firo fall in love with Ennis.
Ryôgo Narita wanted to create a character that didn't act like he looked, so he made the outlaw Jacuzzi Splot a shy crybaby, and gave a large sword tattoo on his face.