Question: Who played thanos in gardians of the galaxy?
Disambiguated questions and answers: question: Who played Thanos in Guardians of the Galaxy (TV series)?
Who played Thanos in Guardians of the Galaxy (2014 film)?
Who played Thanos in  Guardians of the Galaxy: The Telltale Series?
answer: Isaac C. Singleton Jr.
Josh Brolin
Sean Gunn
Jake Hart
Natural Questions answer: Josh Brolin (from the Wikipedia article "Guardians of the Galaxy (film)")