Ulrike (ウルリーケ) is an 800-year old oracle with the form of a young girl. Ulrike comes from a long line of priestesses each chosen by Shinou to act as a channel between him and the people of Shin Makoku. She succeeds Ondine, whose final assignment after retirement was to get Yuuri to form a pact with the elements.
Ulrike is the one who, at the order of and with additional powers from Shinou, transports Yuuri to and from his world to Shin Makoku. Just like all other priestesses, she is not permitted to leave Shinou's castle. Yuuri however, once tried to take her out to show her the beautiful world outside, but Wolfram barged in thinking he was flirting with her.
During episode 44 in the anime, her "childhood spirit" escaped from her body and went outside to play. Her skills frightened the other children and caused chaos in the village. Ulrike chased after her younger form, and revealed her ability to take on the form of a young woman (as opposed to her current childlike one) to "comfort" her younger self.