Chest[]
For me, Kai dropped an Ornate chest that contained 6 identical Mark of the Adumbrate necklaces. Being greedy, I rushed back and forth to the closest bank I knew of with carrying one necklace each trip and stashing it in common storage. I was able to collect all six before the chest timed out. You may feel that the necklace isn't worth the trouble - the Poison Soaked Pendant is better.