Leonardo, commonly nicknamed Leo, is a superhero appearing in Teenage Mutant Ninja Turtles comics and related media, and created by American comic book artists Kevin Eastman and Peter Laird. He is one of the four central characters of the franchise, along with his brothers, Raphael, Donatello, and Michelangelo. Leonardo is the oldest turtle and the fearless leader of the group. Often viewed wearing an ocean blue bandana, his signature weapons are a set of two katana (or ninjatos). Leonardo is the leader and strategist of the turtles. He's traditionally portrayed as the most mature and disciplined of the Turtles, displaying a stoic demeanor and a strong sense of responsibility. Like his brothers, he is named after an Italian Renaissance artist, in this case Leonardo da Vinci. In the original comics, all four of the Turtles wear red masks, but for the creators to tell them apart, he was written and redrawn to have an ocean-blue mask. Source: Wikipedia (en)