This is the relevant information: Olivia Cooke as Art3mis / Samantha Cook, a well-known Gunter who works with various allies to ensure the OASIS is kept free and out of the hands of IOI.
This justifies what answer for what question? Q & A:
Passage: Tye Sheridan as Parzival / Wade Watts, a Gunter who wishes to win so he can leave the stacks. Olivia Cooke as Art3mis / Samantha Cook, a well-known Gunter who works with various allies to ensure the OASIS is kept free and out of the hands of IOI. Ben Mendelsohn as Nolan Sorrento, the CEO of Innovative Online Industries who seeks full control over the OASIS. Lena Waithe as Aech / Helen Harris, a Gunter and long-time friend of Wade's who works as a mechanic in the OASIS. T.J. Miller as i-R0k, a freelance dealer and mercenary often employed by IOI. Simon Pegg as Curator / Ogden Morrow, a co-creator of the OASIS, who eventually left the company. He is concerned about how many people have developed an unhealthy dependency on the game. Mark Rylance as Anorak / James Halliday, the deceased co-creator of the OASIS who reveals an Easter Egg hidden in the OASIS after his passing that grants control over the OASIS to its winner. Philip Zhao as Sho / Zhou, a Gunter and one of the "High Five". He is 11 years old in reality. Win Morisaki as Daito / Toshiro, a Gunter and one of the "High Five". Hannah John-Kamen as F'Nale Zandor, IOI's head of operations in the physical world and for their indentured servant programs.

Question: Based on this passage, who is playing artemis in ready player one?
Olivia Cooke