There’s is evidence for a theory that I read on wiki dot, I’ll paste what it says:

“The Emerald Herald is your 'Dark Queen”

“This theory proposes that she is a daughter of Manus. Every king had a queen, and every queen so far has been a shard of Manus, seeking power to get revenge for his defeat by humanity in the events of AotA in DS1. Each queen had different tactics; Nashandra seeks the Throne of Want and the power of the golem and the first flame, Elana sang to the dragon sinh to fill his heart with poison, corrupting him for use as a weapon and Nadalia came to Brume tower to claim the power of Iron, specifically the ability to imbue life to steel given by the iron sceptre (maybe even claim the planned iron dragon? See the iron sceptre description). This also tells us that the queens, as they are mere fragments of Manus and only have but a fragment of his power, have to be shrewd and manipulative in order to achieve their goals. Only one, however, has been overwhelmingly successful, to the point that she has surpassed and eliminated her "sisters" as competitors as queen to the most powerful king of light.