User blog comment:B214/Question and Answers 2/@comment-24098614-20140226105750/@comment-1359322-20140226112029

Yasaka is the one controlling the flow of the spiritual energy in Kyoto, without her the flow would be disrupted, but there has been no mentioned that they can't leave Kyoto, it's not like their lives are linked to the land, it's their duty that's all. Kunou will eventually take over the role.

As to why there is no illustration of Yasaka, it's not like she is playing any huge role, so there is no illustration for her.