Tony Stark, also known as Iron Man, is a genius billionaire inventor and philanthropist. In Avengers: Endgame, he plays a crucial role in the effort to reverse the catastrophic events caused by Thanos. After inventing his Iron Man suits, Tony becomes a key member of the Avengers, using his intellect and resources to combat threats. In Endgame, he is instrumental in the development of time travel technology, and ultimately sacrifices himself to defeat Thanos, saving the universe and leaving a lasting legacy.