There was indeed a perfect scheme hidden behind what the Dark Princess said.
During the Dark Era, when the Dark Empress arrived in this known universe, she found out that her power as the Dark Fiend was restricted by an external force, one that she could wiggle her way out of on her own.
The restriction prevented her from separating her body into its various forms.
This brought down her power so much that she had to resort to using her domain to create Dark Fiends, or at least that was what they were called back then.
Later, during her unholy conquest, she found that the only way to lift the restriction was to fall to the sword of a particular person... The cure for her curse was to fall to the sword of one of the dangerous beings who dominated the dark era.
"Kael Duskbane, the captain of the Night Riders." The Dark Princess looked beyond Nara and her team, gazing back at Uncle Drew.
