|Title || Ser|
|Book(s) || A Game of Thrones (mentioned)|
Willum is a knight in the riverlands. He is old. He may possibly be the Knight of Sherrer.
A Game of Thrones
An old man from Sherrer once worked in Ser Willum's stables. Using the knowledge he got there, he could tell that those who raided Sherrer rode horses that were meant for war.