Terry seems to have reintroduced Esk in answer to all the people who kept asking "Whatever happened to Esk?" But then (possibly out of sheer devilment) dropped some more questions about her.
Hi Ka... welcome to the site.
I just finished I Shall Wear Midnight too and was wondering exactly the same thing. I thought it referred to Preston and read the rest of the book hunting for another reference. And found none. I thought it referred to one of the men during the stubble burn, but the only two men there are Roland and Preston...... Esk can time travel... so it could be anyone. I wanted at LEAST a hint.