Princess Kraehe loves Mytho and wants him to love her back. But, Mytho loves Princess Tutu and doesn't love Kraehe at all. To make Mytho love her, she dips one of Mytho's heart shards (the feeling of love) in raven's blood. That blood, possesed him into a manipulator. He jumped out of the window and told people that Fakir pushed him.
In the season finale, Princess Kraehe figured out that she is not a princess crow, she is a human and the raven stole her and raised her to catch the Prince's attention and sacrifice it's heart. Once the Prince's heart completed he decided to marry Rue, it's alter ego Princess Kraehe, and live happily.