Leo

Leonardo, nicknamed Leo, is a fictional superhero and one of the four main characters in the Teenage Mutant Ninja Turtles comics and related media. He is the oldest of his four brothers, as well as their commander and tactical advisor. He is often depicted wearing a blue bandanna. His signature weapons are two Ninjatos, commonly confused as Katanas. Leonardo is the eldest brother and the leader of the group. He is the most skilled, the most serious, the most spiritual, the most mature, the most disciplined and the most in-line with Splinter's teachings and thoughts. Like all of the brothers, he is named after an Italian Renaissance artist, in this case Leonardo da Vinci. Leonardo da Vinci is widely considered the most diversely skilled individual of the Renaissance period, and as such Leonardo is also considered the most diversely skilled ninja turtle. In the Mirage 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.