Who is she/what has she done?
Diana is a main character in the Zero Escape game, Zero Time Dilemma. While partaking in a mars mission simulation, she becomes the leader of the "D-Team" in a death game, beyond her will, after she is kidnapped alongside the other participants. Diana has the "SHIFT" ability, an ability that lets one transport their consciousness across space-time. By the end of the game, she has gained a resolve to save the world. Diana's backstory involves her being a victim of domestic abuse at the hands of her highly abusive husband. Her kindness was such that she would not allow herself to remove him from her life. She ultimately forced herself to sign up to the mars mission test, to ensure that she had no choice but to stay away from him.
She is partaking in a death game, but beyond her own will. In certain game timelines, she is forced into killing other particpants. In one timeline, she gets trapped alone for the rest of her life with Sigma Klim in an underground bunker, which causes her to fall into a depression and gain momentary selflessness towards Sigma's own feelings.
Diana is an extremely kind and selfless pacist. During the death game, she always acts as the voice of selflessness, trust, and reason. She doesn't want anyone to get hurt, and is one of the only characters to always remain extremely happy when the death count remains at zero. Diana refuses to ever resort to the violent means, or any means that require her and her team to hurt/betray/not trust others. Even in the timeline in which radical-6 gets released to the outside world, Diana cannot bring herself to kill Phi and burn her body, despite Phi's own pleas for her to do so as it would prevent a timeline of events that would lead to the eventual downfall of the human race. She feels so torn regarding this that she feels as though she is responsible for 6 billion deaths.