Well if that'd be true and my theory be true, Nyx is Hades's wife and the mother of Thanatos like she is in the myth. Morrigan I can totally see being the mother of witches and what if she is a fairy like her surname would imply "Le Fay" = "The Fairy".
V24 cover which was shown at the event. First cover I believe with officially no logo. I cropped it in paint from the video that recorded the DxD event.