I just love kitsune lore, so I'm interested in playing a fox youkai. Since you said that the Mitsumine clan has a lot of undeveloped land, my fox, Junkojuro, could be an old spirit that has coexisted peacefully on this land with the clan. Whereas priests/priestesses are mediators with the spirits on the side of humans, Junkojuro, being old and experienced, communicates with the humans to keep the many spirits appeased. His history of service has been sporadic with various levels of involvement with the family depending on the head, but most leaders have treated him as an ally. Junkojuro does his best to keep peace between the spirits and humans, and he informs the Mitsumine clan of ways that they could quell spiritual unrest without violence and before it escalates. He deplores the concept of Youkai hunting with only a few exceptions given to the truly malign spirits, but would rather deal with such problems himself than have the humans interfere. In exchange for cooperation, he has been known to grant the family favors. As a fox, he can often see where good fortune is, and use his supernatural families to solve any problems that the family may be having. 

Junkojuro's existence would be known only to the highest echelons of the family, essentially the family head and whomever he decides to tell. Currently, Takeshi is the only one likely to know of his existence, and it is up to you whether or not he has been introduced to the heir yet. When he is on the grounds, those with heightened spiritual awareness would be able to see his true form, but to everyone else he can appear however he likes. The potential for escalating conflict between the clans has become a concern to him, and so he involvement with the Mitsumine's affairs has been increasing over the past five years, and especially now that there is a new heir. He wants to get to know the heir and see what his dispositions are. Will Junkojuro ultimately end up being a powerful ally or a deadly enemy?