Karen Sheila Gillan (born 28 November 1987) is a Scottish actress, director, and screenwriter. She is known for the role of Amy Pond, companion to the Eleventh Doctor, in the BBC science fiction series Doctor Who (2010 -- 13). In film, she has starred as Jane Lockhart in Not Another Happy Ending (2013), Kaylie Russell in the horror film Oculus (2013), and Nebula in the Marvel film Guardians of the Galaxy (2014) and its sequel Guardians of the Galaxy Vol. 2 (2017). She took part in the upcoming films Jumanji: Welcome to the Jungle (2017), Avengers: Infinity War (2018) and its untitled sequel (2019). In 2017, she wrote and directed her first feature film, The Party's Just Beginning.

Answer this question based on the passage: who plays nebula in guardians of the galaxy 1? Let's have some stream of consciousness first.
The relevant information is: In film, she has starred as Jane Lockhart in Not Another Happy Ending (2013), Kaylie Russell in the horror film Oculus (2013), and Nebula in the Marvel film Guardians of the Galaxy (2014) and its sequel Guardians of the Galaxy Vol. 2 (2017). So, the answer is Karen Sheila Gillan.