Clear Pheonix island. It will consist of 4 waves:
All Phoenix's
4 Phoenix Firesurgers
4 Phoenix Windsurgers (leave 1 if you are farming pheonix eggs, island will respawn in 15-30 minutes)
Melernil Faal`Armanna
Once this is down, the Avatar of Mist will spawn where the "an apparition of mist" is.
If "a flaring pheonix" is up, then phoenix island has been cleared and you have to wait 6 hours for respawn of the island.