[Ah, this. Koumei shifted into a sitting position, moving carefully so as to not disturb his injuries any further, and regarded Cao Pi with tired eyes.]

I came from the battlefield of a civil war, Lord Zihuan. One of my brothers wanted the throne for himself, but didn't tell anyone when he was given the opportunity. Thus, his anger and resentment drove him to take over the capitol while the rest of us were away...and it was only when I was struck down that I realized he had outside assistance.

[It was the simplest explanation he could come up with, given the complicated politics within the royal family alone. Stating anything further might get confusing.]