Raphael is the Teenage Mutant Ninja Turtle associated with the color red in most adaptations.
The color-coded masks became especially important in the 1987 animated series and the toy line. In that widely recognized version, Raphael wears a red mask, Leonardo wears blue, Donatello wears purple, and Michelangelo wears orange. These colors help audiences distinguish four otherwise similar green turtles.
The original Mirage comic used red masks for all four turtles, so the color association is not universal across the franchise’s history. Later adaptations generally adopted individual colors, making Raphael’s red mask one of the best-known visual conventions. His red coloring complements his intense personality and his traditional use of sai.