Arcturus would lose face if he retracted his challenge after delivering it in front of members of half the Great Houses. So why would he, when he was the most powerful mage alive, confident of winning the duel? His victory would avenge the humiliation of his father twenty years ago, and serve as the ultimate sign of the ascension of House Nightfeld above House Redbriar. The Nightfeld brothers were bullies. Handsome bullies, and ones I shared a mutual enemy with, but bullies nonetheless.
