The world is desperately waiting for Avengers EndGame. The finale to infinity saga is expected to be not only action packed but also emotional. Thanos was able to fulfill his destiny by wiping out half the population. The Avengers are toast and lost. Tony Stark is lost in space, Captain America is mourning the loss of his friends and Thor is remembering his legacy. The Marvel trinity is desperately waiting for the right moment to kill the mad titan. Personally i feel Tony Stark and Thor are the major contender to kill Thanos. Russo Brothers have perfectly set up an exciting finale to Marvel Cinematic Universe.
Tony Stark has been the godfather of Marvel Cinematic Universe. Robert Downey Jr paved the path for huge critical and commercial of MCU. Thanos was inside Tony Stark head for six years. Thanos and Tony Stark shared an interesting relationship. The mad titan was aware of the legacy of Tony Stark. Stark showed his courage and battled the mad titan. But was defeated very badly. The defeat against the mad titan resulted into decimation of half the population. Tony had to see his friends die. The death of Peter Parker damaged Tony very badly. He had to see his son die right in his arm. The rage Tony Stark possess is far from imaginable. I will literally scream in joy if Tony Stark is the one to kill Thanos.
Thor Odinson has been in the MCU since 2011. The god of thunder has an integral part of MCU. Taika Waititi was able to create a magical story line with Thor. The character has evolved since Thor Ragnarok. The most powerful Avenger has been through a lot. The mad titan killed his brother, best friend and citizens in front of him. The god of thunder lost everyone he cared in his life. Thor was so close to killing Thanos but was not successful. If Thor aims for the head this time, it will be a great moment in the movie.
Apart from Thor and Tony Stark, Captain America and Carol Danvers are other major contender to Kill thanos. When Thanos gets killed, it will be the most satisfying ending in Marvel history. Personally i would be very glad if the original Avengers are the one to give final blow to Thanos.