Tarecgosa

Tarecgosa is a powerful member of the Blue Dragonflight.

Background
Once you have seen the horrifying fate of Azeroth, Anachronos will task you with the creation of an Eye, which will be used to see further into the events that are unfolding at Coldarra.

After the creation of the Timeless Eye, you must then bring it to Coldarra and "search out a place suitable for the Eye's activation." When you have arrived at Coldarra, you are stopped by Tarecgosa, who warns you that this place is no longer suitable for your kind.

Tarecgosa asks you to meet her inside the Nexus, where she will escort you through a special, quest-only version of The Nexus. She will aide you in fighting many of Arygos' Twilight wardens as you travel to the center, to the Nether Vortex. You must fight your way through, defeating a ferocious twilight dragon named Thyrinar. Once there, you must then use the Timeless Eye to access the previously obscured vision.

Once you have seen the vision in The Nexus, Tarecgosa tasks you to deliver information on what you have seen to Kalecgos at Nordrassil in Mount Hyjal. Later you must travel with Kalecgos back to Coldarra.

However, Arygos has betrayed Azeroth to Deathwing, and Tarecgosa sacrifices herself to save Kalecgos. Kalecgos saves her life by binding her soul to you, but the binding is not permanent, and must be strengthened with materials from the Firelands. You then take Tarecgosa's form to attend the draconic council, and thus are directly responsible for the choosing of the new aspect. Upon defeating Ragnaros and procuring his heart, the staff is completed and imbued with power thanks to Kalecgos, and provides a permanent home for Tarecgosa, who will be your friend and companion.

Quotes

 * "Wha? What foolishness is this?
 * "You there! Have your senses abandoned you?!"
 * "Coldarra is no place for mortals now."
 * "You must leave at once if you value your life."