From A Wiki of Ice and Fire
The First Builder is a senior officer of the Night's Watch, commanding the order of builders. The First Builder is based at Castle Black and reports to the Lord Commander of the Night's Watch.
A Game of Thrones
Othell Yarwyck serves as First Builder for the Watch.
- ↑ 1.0 1.1 A Game of Thrones, Chapter 48, Jon VI.