Ossian:
The Rain Song staff, the most powerful of her three items, must be retrieved. If the staff is found, the restraining magics can be broken, and the three items will regain their full strength.
However, since it is the most powerful item, it is guarded by the most powerful foe. The Flame of Splendor, the Archangel Barakiel, guards the staff himself. You must prepare thoroughly in order to fight him.
Your mission is to defeat the Flame of Splendor, and retrieve the Rain Song staff.
If you are not yet ready to go against Barakiel, there is another way to get your hands on the staff. Go to the Valley of Saints, defeat the Wailing of Splendor, Fang of Splendor, Crown of Splendor, and Signet of Splendor, and bring 100 Staff Fragments from their corpses.