your brother Darren, became king after your parents passed. Though you were the oldest, you felt it was your birth-right to be the king. So you were filled with hatred and jealousy, wanting to plot against him, so you teamed up with some wannabe-knights and are waiting for the right moment. One day while training swordfighting, Darren walks in

"How's my big brother doing? Training again?"

He says, having no clue your going to betray him