Joss Whedon wrote the film treatment for X-Men, co-writer of Captain America: The First Avenger, the co-writer and director of The Avengers and its sequel The Avengers 2. He will also co-write and develop live-action tv series set in the MCU. Whedon is also known for directing the hit televison show, Buffy the Vampire Slayer and its spin off series, Angel. Some other shows that Whedon has worked on include Firefly, Serenity, and Dollhouse. He is also a comic book artist and has worked on The Astonishing X-Men series.