Blue Beard is a seemingly stern and intimidating man. He was courting Amalie, but she didn't like him. It turns out that Blue Beard was married previous to several other women, and all of them mysterious disappeared.
Through some weird coincidence Ludwig looks almost exactly like his first wife. Blue Beard is oblivious to the fact that Ludwig is a guy and takes him back to his castle. There Ludwig finds out that Blue Beard's beard is a fake. The beard helped Blue Beard become another person because without it he was a weakling who cried easily. Ludwig also discovers that Blue Beard murdered all of his previous wives. He had given his wives keys to every room in the castle, but forbid them from going into a certain room. His first wife, Annie, disobeyed him and went into the room anyway and discovered his secret about the beard. Annie felt that it was not the beard that magically made him not a weakling, but himself. She wanted to Blue Beard to step out as himself, but Blue Beard felt that she purposely wanted to disgrace him--so he killed her. The very same fate fell upon each and every one of his wives after that.
Blue Beard attempted to kill Ludwig as well after finding out his secret, but is impaled by a weather vein in a freak accident. Using his last breath he regretted ever killing Annie because she was the only women who had ever loved and accepted him for who he was.