Drosselmeyer
This is probably one of the most indirectly involved characters of the show. In all actuality, he is the cause of every event that happens. It seems that Drosselmeyer was the one who wrote the story, The Prince And The Raven. In a sense, he is the creator of the Prince, Knight, Princess Tutu, and Princess Kraehe. He is the person who originally gives Ahiru the ability to be a human girl, and afterwards, the pendent which changes her into Princess Tutu. Drosselmeyer watches every event that unfolds in their world, and interferes when his puppet, Edel, cannot so things follow the flow of the story accordingly.