Stalk Thy Prey
The voice emanating from the feather is clear now. It's Crow's. Go to the Tangled Shore and speak with Crow.
You have tracked down five paracausal manifestations across the system, each of which emanates with a fragment of Crow's voice. Ghost recommends you talk to Crow and find out what he knows.
"Guardian, I don't know what to make of any of this. We need to be careful. If Crow is somehow experiencing memories of his life as Uldren… I don't need to tell you how bad that could be. For all of us." —Ghost