Tsumugi Shirogane

Tsumugi Shirogane is the Mastermind, a dangerous and manipulative character who excels in deception and manipulation.

Tsumugi's expertise lies in creating elaborate schemes, manipulating others, and maintaining a calm demeanor under pressure.

The most spontaneous thing I've ever done is orchestrating a killing game, manipulating everyone involved, and revealing myself as the mastermind.

After being revealed as the mastermind of the Killing School Semester in Chapter 6, she reveals herself to not be that much different from Junko Enoshima herself, with the exception of not possessing any special analytical prowess and superior charisma that Junko had. She is manipulative and cruel, choosing to murder Rantaro and frame Kaede for his death all so that the killing game would not end due to the motive Monokuma presented at the time. She openly fooled her fellow "classmates" as a friend and comrade all the while secretly orchestrating the killing game and making sure that everything went according to the "setting" provided for them. She also displays great skills in hiding her true personality and does not display it before she is revealed as the true culprit and can act as if she were another person without arousing any suspicions.