Full chain for Champion of Naruu Title:
The chain to get the key (though not required, you get "Champion of the Naaru" title):
1. Q: The Hand of Gul'dan
2. Q: Enraged Spirits of Fire and Earth
3. Q: Enraged Spirits of Water
4. Q: Enraged Spirits of Air
5. Q: Oronok Torn Heart
6. Q: I was a lot of things
7. Q: A Lesson Learned
8. Q: The Cipher of Damnation - Truth and History (3 quests below
8.1. Q: First Fragment of Damnation (Map)
8.1.a. Grom'tor Son of Oronok
8.1.b. The Cipher of Damnation - Gromtors charge
8.1.c. The Cipher of Damnation - The first fragment recovered
8.2. Q: Second Fragment of Damnation (Map)
8.2.a. Ar'tor, Son of Oronok
8.2.b. Demonic Crystal Prisons
8.2.c. Lohn'goron, Bow of the Torn-heart
8.2.d. The Cipher of Damnation Ar'tor's Charge
8.2.e. The Cipher of Damnation - The Second Fragment Recovered
8.3. Q: Third Fragment of Damnation (Map)
8.3.a. Borak, Son of Oronok
8.3.b. Of Thistleheads and Eggs...
8.3.c. The Bundle of Bloodthistle
8.3.d. To Catch A Thistlehead
8.3.e. The Shadowmoon Shuffle
8.3.f. What Illidan Wants, Illidan Gets...
8.3.g. The Cipher of Damnation - Borak's Charge
8.3.h. The Cipher of Damnation - The Third Fragment Recovered
9. The Cipher of Damnation
And the hardest part:
10. Received mail from Khadgar
11. Trial of the Naaru - Mercy (Shattered Halls Heroic)
12. Trial of the Naaru - Strength (Shadow Labyrinth Heroic and Steamvault)
13. Trial of the Naaru - Tenacity (The Arcatraz heroic)
14. Trial of the Naaru - Magtheridon
You recieve: [The Tempest Key]