Tengu Onmyoudou

The gifted, confident onmyouji Yasunari was dispatched to investigate a powerful ruler's violent behavior change and the suspected spiritual powers behind it. His only lead takes him deep into the mountains, where he meets a young man named Ushiwakamaru. Yasunari approaches Ushiwakamaru and quickly determines that he is no threat. However, Ushiwakamaru mistakes Yasunari as a tengu and asks him to teach him how to use a sword! What exactly is Ushiwakamaru hoping to accomplish?