This quest is no longer available within the game.
Travel to the Temple of the White Tiger in Kun-Lai, the Temple of the Red Crane in Krasarang, the Temple of the Jade Serpent in the Jade Forest, and Niuzao Temple in Townlong Steppes to obtain four blessings of the celestials. Complete ONE of their four available challenges.
Speak with Yu'lon
Speak with Chi-Ji
Speak with Xuen
Speak with Niuzao
Complete one of the Celestial's Challenges
I would like to grant you my full array of draconic power, but sadly, it would tear your mortal frame apart. Still, it's not hopeless - I believe I can create a powerful vessel that you can use.
To craft it, I will need the blessings of the four August Celestials in Pandaria. Travel with me to the four temples and we will speak to each. To be worthy of their gifts, you must defeat one of their challenges.
They will not be easy - chose the one challenge best suited to your equipment and skills!