Although Miley is called "The Laughing Doll", she isn't as friendly as her name seems to hint.

Miley is sadistic; enjoys seeing the participants in the death game suffer, and even goes as far to torment them by dangling hope before crushing it. She enjoys toying with their despair as the participants start questioning their chances of survival.

Miley also has her own plans and agenda, dropping valuable clues to Sara even as she mocks her. She doesn't care about Sara personally, but she derives amusement in seeing how she and the other participants will react to unexpected information.

After three of the keys from the First Trial are used on a small yellow box, Miley's head falls out revealing a note, requesting to be put together. The participants of the death game, excluding Nao Egokoro, Reko Yabusame, and an unconscious Kanna Kizuchi would begin looking around the first floor for doll limbs. After Sara and Sou venture the first floor they are both able to find the arms, body, and legs, gathering everyone together to put together the doll. White smoke fills up the room after the head is placed onto Miley, and when said smoke clears up a standing Miley appears in front of the participants. 

After this occurs a vote is held to practice the use of 'majority vote'. After the votes are brought in, Miley executes Kazumi Mishima via an electric collar which burns through his neck, leaving a stunned Nao heartbroken through the rest of the chapter. After she makes fun of Kanna, Kai Satou hits her face with one of his frying pans, leaving her bleeding and swearing revenge.

Miley next appears in the main game where she supervises the executions. After the final vote, Miley executes Joe Tazuna, par to him being the sacrifice, using blood-sucking tubes. Before starting his execution Miley hands Sara a button which is described to slow down the execution and has a possibility of ending it if pressed enough. After Sara tries to stop the execution from happening, which ends up failing, Miley mocks Sara saying the button would've never stopped the execution in the first place. Redirecting her attention to Kai, Q-taro Burgerburg runs up and restrains her from activating the execution, while Kai is left bleeding from stabbing himself, eventually dropping dead.

When the third floor is opened, Miley only makes minor appearances, first giving Sara the percentage sheets. When Sara and Keiji later venture the first floor once again to find a missing Gin Ibushi, a Miley doll can be seen idly sitting in a hidden room. Miley can then be seen talking to an unknown person on the first floor, but they are quickly interrupted by the card trade alarm on Sara and Keiji's tablets.