This quest is the culmination of a couple different quest lines from Witch Doctor Uzer'i. Completion of  Natural Materials and the Muisek chain allow you to receive this quest and your choice of one of four rare weapons.
Witch Doctor Uzer'i wants you to wait for a moment while he prepares the weapons.
Imbuing the muisek into the weapons is a difficult process. Now that I have all of the required materials and the muisek of the creatures that you captured, I may begin. Please wait; I will return in a moment.
Did you get it yet?
As promised, you have your choice, <name>. The muisek of the creatures has been forever sealed into the power of these weapons.
You may now wield their energy as your own. Use it well.
- Breadcrumbs:  The Wilds of Feralas,  Hero's Call: Feralas!, or  Warchief's Command: Feralas!
- Welcome to Dreamer's Rest / Camp Ataya
-  Signs of Change
-  More Than Illness
-  Tears of Stone,  The Land, Corrupted
-  Sealing the Dream
-  General Shandris Feathermoon /  To Stonemaul Hold
- Feathermoon Stronghold (Alliance side quests)
-  The Battle of Sardor
-  Hatecrest Forces,  General Skessesh
- Breadcrumb:  Report to Silvia
- The Dire Maul threat: Tower of Estulan / Stonemaul Hold
-  The Gordunni Threat
- Side Chain:
-  The Gordunni Orb
-  Estulan's Examination /  Talk to Swar'jan
-  Ogre Abduction
-  Gordok Guards,  Rulers of Dire Maul
- Forces of Nature Part 1 / Weapons of Spirit Part 1:
-  Forces of Nature: Wisps /  Testing the Vessel
-  Forces of Nature: Hippogryphs /  Hippogryph Muisek
-  Forces of Nature: Treants /  The Flow of Muisek
-  Tell Silvia
-  Might of the Sentinels /  Might of the Stonemaul
-  To Camp Mojache
-  The Lost Apprentice /  The Darkmist Ruins
-  The Darkmist Legacy,  Ancient Suffering
-  Verinias the Twisted
-  Return to Vestia /  Return to Sage Palerunner
-  Adella's Covert Camp
-  War on the Woodpaw
- Horde-only side chain
-  Woodpaw Investigation
-  The Battle Plans
-  Alpha Strike
- Forces of Nature / Weapons of Spirit Part 2:
-  Treant Muisek
-  Forces of Nature: Faerie Dragons /  Faerie Dragon Muisek
-  Forces of Nature: Mountain Giants /  Mountain Giant Muisek
-  Weapons of Spirit
-  Stinglasher,  Zukk'ash Infestation
-  Sasquatch Sighting
-  It's Not "Ogre" Yet,  The Hilltop Threat
-  Taming The Tamers
-  Spiteful Sisters,  Twisted Sisters
-  Ysondre's Call
-  Taerar's Fall
-  Ysondre's Farewell