Among the sea of purple and orange rally towels at the Phoenix Mercury game on Saturday night are gold and black jerseys. If you look closely enough, you can see dragons outlined on the sides and the name "Sorrengail" under the number four. But it isn't the jersey of the visiting team. The gold and black custom jerseys are for Fourth Wing Night, the very first of its kind themed night in the WNBA. Fourth Wing is the first book in bestselling author Rebecca Yarros' Empyrean series.