Grand Duke Antoine
About
Antoine was the Grand Duke who lived centuries prior to the start of the story, in the same period when the war against witches took place. He fell in love with Lorelei and even broke off his engagement to a noble girl for her. His life falls apart when he finds out that Lorelei is a witch and assumes that she'd used a love potion on him, losing his knighthood and the respect of the other noble families and gaining a burning hatred towards witches.
After he finds out that Lorelei is carrying his child, Antoine curses it to live in hatred and be betrayed by their loved one.