Possible magical guardians vs. dark fight solo adventure?

we know that the theme for BG season 2 is: Magic of Azeroth. Its where the ‘Magical Guardians’ are teaming up to fight against Malygos and his powerful Dark Flight.
I wish that this story can be a possible solo adventure. it could be the most epic solo adventure yet, we know who the magical guardians are: Elise, Dawngrasp, Reno, Edwin, Aranna, Liadrin, Tyrande, and Nemsy. the question is: how did they become the Magical Guardians?