My vision is blurry and I can't seem to concentrate as much as I'd want to, but here I go. (Also, I appreciate the offer, thanks, you're awesome for accepting such a silly request
).
They might be called spirits here, but the use of the word then meant a state of knowledge or enlightenment, so I dunno what to call them on this here RP.
Kitsune come (usually) in two varieties, Myobu (or Zenko) and Nogitsune (or Yako), the first follow the rules/orders/what-have-you given by Inari and the latter don't. Inari is the god/goddess of fertility, rice, agriculture, foxes, industry and worldly success, though maybe in this setting a powerful spirit, important ancestor/hystorical figure or similar would be more appropiate. I dunno, maybe Thor, Odin, Quetzalcoatl, Shiva and such are important spirits tasked with watching over their respective lands. Whatever works I guess.
Both of them
can be tricksters and sneaky, and play pranks on people that offend them and the like (they are known for their reputation for vengefulness in some cases). The key difference: Nogitsune are very likely to be disproportionate on their "pranks" or wander off and become actually malicious and do it to torment people, though not always the case (though it's easy to tell that they aren't much of a team player); Myobu go the flip side and are more likely to be overall nice and good, maybe curse evildoers instead of just someone they don't like (unless, again, the disliked one
really gets on the Myobu's bad side). Stories tell of kitsune playing tricks on overly proud samurai (the prideful in general seem to be a common target), greedy merchants, and boastful commoners, while the crueler ones abuse poor tradesmen and farmers or devout Buddhist monks. Other, simpler goals are seduction or food theft, notice that the former isn't necesarily a bad thing, many of them are presented as good wives/lovers in romantic stories or just friends/guardians.
Both of them don't necesarily share regular human morality (so beware, a kitsune paying a host/companion for sharing the house may be stolen goodies or money from the neighbors, though if it's Myobu we're talking about it's likely they stole the items from a thief) and don't like owing someone favors, so treating some them with respect usually works to make them decide to stick around and help you or at the very least prevent the Nogitsune from finding you an interesting chew toy (though do be wary of them, lest they start demanding more and more stuff).
It's little star ball is priceless to the kitsune it belongs to, but worthless to whoever might get ahold of it. It can be used to secure a favor, though you might need to convince the fox first, be sure to either get the kistune to propose it or promise it if you make the suggestion; kistune stick by their word. The gifts they grant are usually of immaterial nature, good fortune and such; if the kitsune isn't living with you or repaying some good deed, payment with shinies or valuables should be regarded carefully and also try to extract a promise that it's real.
Kitsune, if they are strong enough, may even have a shrine for themselves in a forest they live in or somewhere related to them, like a town they protected.
Illusions and magic would better be discussed at a later date, as it's stuff I'd talk about anyways regardless of whenever or not it's a kitsune I'm using. I'm not sure of stuff I missed, I'll check back later.
