Book: The Taken King.
“Yep, yep. All thanks to me. I know, we thought we had a good thing with that coven of Wizards, but it took a real field commander to see how easily intelligence can be misread. Now that the Guardian's cleared out the Echo at King's Watch, I think the old Cosmodrome's going to be just fine.” - Cayde-6, after-action report to Zavala