Rise of the Forgotten Kings
Elven "goddess" turned Green Dragon
Once an elven goddess, Arashe was spurned by her love Corellon Larethian, and proceeded to take out her jealous rage by gathering an army of Wild Elves to destroy him. Banding together, the other sub-races defeat the Arashnites, with Corellon delivering the final blow to Arashne.
The goddess had been reborn as the Green Dragon, creating a new army of followers in the Elven Forests, but she was eventually dispatched by Team Trust.