these are datamined voice lines from Shadowheart
"I would strike through -- but in whose name?"
"In the Moonmaiden's name."
"The Moonmaiden smiles upon me."
"Selûne, arm me with your silver light."
"I am Her seventh, cloaked in silver."
"Cower from her light!"
also, an NPC was labelled as "a Selune cleric who knows Shadowheart"
some information could also be found when you play as a sorcerer.
when Shadowheart has weird silver light that appears on her left hand. As a sorcerer, you have unique dialogue options with her when that happened. Through those options, she tells you that the power inside of her feels very familiar
