Champion of the Naaru is a special title that is given to players who have completed a couple of Quest chains to result in attunement for The Eye in Tempest Keep and for Serpentshrine Cavern in Coilfang Reservior.
The actual NEED for attunement to enter these 25-man instances was lifted as of Patch 2.1.2 which was quite a while ago, but as of Patch 2.3.0, the title was introduced as a way to allow people to discern themselves from others who had not completed the quest chains.
So, basically, right now it's just a social marker - something to label you as someone who did something specific, whether or not you did it BEFORE attunements were lifted or not.
I started this quest chain when I was in my brief stint in a raiding guild, but by the time I left, I still needed to finish three more quests to complete it all - two heroics, then downing Magtheridon.
I didn't put any real efforts towards getting the right heroics done until I heard someone mention that the Champion of the Naaru title won't be available once WoTLK releases, in order to prevent players from getting the title on EZ-mode with the new Northrend gear and levels.
What? Something That Won't Be Available Later??
Okay, fine, I figured... I'll get it on my Mage, since he's already very close to achieving it.
Starting The Quest Chains
In order to get the title, a player has to complete the attunement chain quests for Serpentshrine Cavern and The Eye in Tempest Keep.
The SSC quest you can pick up at any time by heading into the Heroic version of Slave Pens and progressing partway through it towards the first boss. Once you've got the quest, you need to venture into Karazhan for Nightbane, and Gruul's Lair for Gruul himself to pick up the items, and then return to Heroic Slave Pens to turn it in.
The TK quest chain, however, requires a pre-requisite quest chain to be completed: The Hand of Gul'dan in Shadowmoon Valley. This quest chain is the longest part of the process, and has a few group quests (Cipher of Damnation) that one level 70 will not be able to solo, so round up your buddies or listen in on the General line in SMV to get in on parties forming for it when you hit them.
For the Shadowmoon Valley quest chain, there's two of those types just about back-to-back (one solo in between) to make it easier to find a group for the second - turn in and stay with the group you're with after you complete The Cipher of Damnation - Borak's Charge so you can work together to complete the final step of [70 G5] The Cipher of Damnation.
Once You've Got It, How To Show It!
I got mine after turning in the Trial of the Naaru final step of killing Magtheridon. I had already long killed Nightbane and Gruul and finished that series.
The process of showing your new title is easy - open up your Character Sheet and select the new title from the drop-down:
