Shadowkeep will have us seeking a quarry of Eris Morn
While undergoing some of the Hive related passages, I glanced at an older ship called Unfinal Shapes. Per Eris, Queen Mara was needing help and provided her insight into an enemy. A quarry as she called it. Given Eris focus and attention in both the trailers and the narrative reveal? She has found the quarry. Is it dead? Possibly. But IF so... then it lead her to the beginning of shadowkeep and thus leaving the Tower per the narrative.
She also speaks the truth in the dialogue how the Tower and its guardians see her as less than a guardian, but the Queen sees her as a hunter. For the overall record, we have seen her as such due to her unique circumstances. The quarry has either evaded her... or is dead per the trailer with her marking.
With the recent dialogue reveal for the narrative?
Eris is going to be upset with something. Her focus is clearly on the quarry which means it is an enemy she is familiar with. Use the thread to theorize on WHO that might be.