Initiative belongs to Thoros, whose sword bites into Xorn's armor again and becomes lodged in a shoulder pauldron. He slides his sword downward and severs a section of it, drawing blood from Xorn.
Xorn responds with another light punch that leaves Thoros unphased, but then you power into his side with your fist. He probably knew it was coming but didn't expect you to hit hard, wounded as you are.
It is when he stumbles back to face you that he notices Melis' blood on your boot.
"I yield," Thoros says, lowering his sword.
The crowd is shouting for blood.