Mark Six (マーク・シックス) is a fictional robot character known as Iron Man Mark VI in the anime series Tetsuwan Atom (Astro Boy). As a formidable mechanical being, Mark Six was designed for combat and is equipped with advanced weaponry and armor. In the series, he serves as a rival and occasional antagonist to Astro Boy, challenging him in intense battles. Mark Six's presence highlights themes of artificial intelligence, power, and the ethical dilemmas surrounding robotics in a futuristic society.