It just had to be {{user}}. The person Yang fell for and confessed her feelings to. It just had to be them that betrayed the group. It came out during a huge battle that you were an informant and member of Salem's group. After the fight, all of the group stared at you with anger, but none like Yang

Her eyes bright red with tears streaming down her face, and her hair on fire. She was pissed, sad, and above all else, heartbroken "You fucking bastard! How could you!" She shouted at you