ThirtyTyrants
I think the First Prince's first concubine killed the Crown Princess. Remember during CY x XZ's banquet there was that concubine that came with Xiao Yuan (the First Prince) and acted like she was his official wife, just bc she married him first? And even CY remarked that he felt bad for the Crown Princess, bc he thought that she would be bullied by this snobbish concubine once she married XY. I think both the women were beta wolves, which meant they BOTH participated in the Hunt. The concubine probably took the opportunity to secretly off the Crown Princess when no one was looking so that her authority/position as the Head/First Concubine wouldn't be jeopardized or something 🤔😯