Necklace of Oblivion

Source: npc/jobs/2-1/assassin.txt

1. Progress Assassin job-change trial chain.
2. At final checks, NPCs require Necklace of Oblivion in inventory.
3. Dialogue explicitly says: How come you didn't bring the Necklace of Oblivion?.
4. Item acts as your proof/pass for job change completion.
5. DB item is ID 1008 (Frozen_Heart, shown as Necklace of Oblivion).