So, this is the Diva of Luna Bay, a, in her words, “mature” lady of skill and renown. Some would likely just say that she’s probably older than Equrestria.  
She’s a little too old to cause havoc anymore, and might even help you on occasion. Though, it does come with a price.
 
Ancient books on monsters reveal that she used to live in one of the bigger lakes in Equestria, distributing cursed and magical weaponry to peasants and urging them to violence and hatred to gain power. She may have been the origin of Flash Magnus’ magic shield (though the shield was originally cursed with her magic, it was purged of the spell ages ago).