Her character is described as the "female lead" in the film. She is promoted using the phrase "Strength, Loyalty, Wisdom." Responding to a Tweet from Haruka Abe which stated that his Snake Eyes was going to blow viewers' minds, Henry Golding described Abe's Akiko as being "insanely bad ass." She is willing to protect the Arashikage Clan at all costs.
She tells Snake Eyes that Cobra is the largest terrorist organization on the planet and they're going to start a war. He tells her that this isn't his fight, and in return, she asks him to tell her why he's there.
When Snake Eyes saved Tommy's life, Tommy introduces him to his grandmother Sen, the leader of the Arashikage Clan and Akiko, head of security. They tell him that he can live with them and become part of the clan if he is able to pass three tests. They warn him that if he fails the third test, he will die. Akiko expresses concern about an outsider being brought into the clan and doubt that Snake Eyes can pass any of the tests. She warns Tommy that Snake Eyes is a "ghost" - that she can find nothing on him when it comes to either fingerprints or facial recognition. Despite this, Tommy is determined to give Snake Eyes a chance. He gives Snake Eyes a katana, Morning Light, an ancient blade of the clan. He tells him of the “Jewel of the Sun,” which his clan vowed to never use, even though it had been given to them in order to protect and serve. He explains that the clan believes in defeating their opponents with honor. That evening, Snake Eyes leaves Arashikage Castle, using a motorcycle that Tommy agreed to let him ride. He is watched by Akiko, who is still distrusting.
After the second test, Snake Eyes is approached by Akiko. The two spar with each other, Akiko promising that she’ll reveal more of her past to him if he can land a blow on her with the blade given to him by Tommy. He faces off against her, but is only able to win using dishonorable tactics, so she does not reveal anything. She is then summoned by Tommy, who has learned that Kenta is back in Japan and is smuggling weapons. He goes to confront him, and Tommy asks to come along. When they get there, they discover that Kenta is in league with a group called Cobra, an international terrorist organization with loosely aligned cells throughout the world. They also learn that Kenta is working with a woman called Ana Decobray, or the Baroness, who killed a U.S. legislator as well as two-hundred civilians in a terrorist attack. Tommy decides they need more help to fight them and calls in Scarlett, a member of an international group of crime-fighters called the G.I. Joe.
They return to the castle, but Snake Eyes sneaks out again, this time pursued by Akiko. He manages to shake her and this time meets up with Kenta and Baroness in a fortified underground bunker. When Snake Eyes again returns to the castle. There, he meets again with Akiko. The two talk and she admits to having been taken in by the clan as a youngster and that they are everything to her. In return, he tells her that his father was killed when he was a young man.
Snake Eyes then takes on the third test. He is told that he must be pure of heart to pass and is made to enter a pit. There he faces off against three ancient anacondas. They sniff at and he centers himself. Things seem to be okay at first, but then the snakes lash out, then coil around him. They have detected that he is not pure of heart. Seeing this, Akiko leaps in to save him. Afterwards, he returns to the castle’s gathering area, where he is told only the full truth will save him. He admits that he has not been honest, that his heart is full of vengeance for the man who killed his father. Sen tells him that for telling the truth, his life will be spared.
That evening, Snake Eyes purposely triggers the castle’s alarm systems. He watches as Tommy and Akiko enter the temple where the Jewel of the Sun is being kept. After they exit, he slips in and uses Tommy’s blood to bypass the security. As he exits, he finds Akiko waiting at the door. She comments that she really did want to trust him, then tries to take the jewel back. She loses and Tommy makes his way to Kenta and the Baroness.
After chasing Snake Eyes, he gives chase in his motorcycle, fending off many of Kenta’s men. He ends up in a confrontation atop a car, where Akiko and Tommy see that he is fighting on their side. Snake Eyes, Tommy and Akiko finally arrive back at the temple. There, they pursue Kenta along with Sen. They eventually corner him and manage to deprive him of the Jewel.
Sometime later, Scarlett approaches Snake Eyes in his room. She tells him that his father had been a G.I. Joe agent just like she is. She invites him to join and follow the family tradition, handing him a file and telling him that her commander, General Joe Colton, wanted her to share it with him. Akiko asks him where he is going and he tells her that he is going to look for Tommy, to try to find him and bring him back. He hands him a bag, containing his iconic black outfit and helmet, which he dons before leaving.