Menae was Cordelia's mother and biological aunt of Carla and Shin.
She was the last firstblood woman and Karlheinz gave her to the Demon Lord (Burai that is Vibora race) as a mistress so Karlheinz could have children with their daughter - Cordelia. She soon died after Cordelia's birth.
She is sister of Krone, making her aunt of Carla and Shin; although she was like a mother to them.
It's also said that she had a piece of jade jewelry containing all of her memories, which she always kept locked away in a small silver box.