April O'Neil is a young human woman who has appeared in virtually every version of the Teenage Mutant Ninja Turtles franchise. April is usually the Ninja Turtles' first human ally in most incarnations, and is generally portrayed as being a very good friend of the Turtles: Leonardo, Donatello, Raphael, and Michelangelo, often acting as a big sister or surrogate mother to them. April's love interest in the franchise is oftentimes Casey Jones, who is also a close friend and human ally of the Turtles.