While there isn't a single "author" of the movies, here's a breakdown:
* Original Concept: The Transformers toys were created by Takara Tomy in Japan.
* Story & Characters: The Transformers characters and story were developed by Marvel Comics (specifically, writers Bob Budiansky and Dennis O'Neil) in the 1980s.
* Film Adaptation: The live-action Transformers movie series was created by Steven Spielberg, who served as executive producer.
* Individual Filmmakers: Each movie in the series has different directors, writers, and producers. For example, Michael Bay directed the first four Transformers films, while Travis Knight directed Bumblebee.
So, while the Transformers franchise has its roots in Hasbro's toy line, the stories and characters were developed by Marvel Comics and brought to the big screen by Steven Spielberg and a team of filmmakers.