Hi I was was wondering if anyone had ever read an author's take on nine-tailed foxes. I feel like they're not really comparable to beasts and are more like immortals/gods but I was specifically wondering if it would make sense if they also had golden cores/jindan. I know that magical beasts have beast cores but could that also apply to ninetailed foxes or would they have a normal golden core like cultivators do (or no core at all)? Honestly idk, do they even use qi or is it some other kind of magic?
...so none of these things actually exist. No comparison can be made across all of the fiction that exists. It would depend on the story you're talking and the author can pull whatever they need out their butt. I'm pretty sure most fiction depicts nine-tailed foxes as almost like succubi who absorb yang qi from men.
Not sure if there is any fixed rule, but in most xianxia novels I have read before, nine-tail foxes are a high-ranking beast tribe, also have the beast core, and they are cultivating similar to other beast tribes, just have difference gongfa, inherited or something.
To my admittedly limited knowledge, in the Legend/Mythology, there was ONE Nine-Tailed Fox, and she was a goddess. There may be other multi-tailed foxes, which were possibly her descendants, but they all had less than nine tails. I think there was also only one Kun-Peng (Giant Fish that transforms into a Giant Bird), just like there's only one Hydra, Cerberus & Pegasus in Greek Mythology. Jormangand'r is actually a great parrellel, as while there are other Sea Serpents, Norse Mythology only has one World Serpent. If you want an explanation as to why there are so many Nine-Tailed Foxes & groups of Foxes intended to grow 9 tails in fiction, well it's the same reason why fiction often have small "Fenrir" & "Cerberus" such that most people have one. Dog's a pets, and they have canine-like descriptions. Excusing that, if you're talking about Cultivation Stories, the specifics would change depending on the story & author. If they don't just have a dantian, they would usually have some sort of dantian-equivalent, be it their Beast-Core, Divine-Core, or Demonic-Core. For all intents and purposes in many of these stories, these Cores are probably the same things as dantian's, but in Animals/Beasts, Divine Beasts, or Demonic Beasts. It can also be common enough for the Demonic-Cores are better for Demonic Cultivator's, and they will quietly never mention the effects of someone using a Divine Beast Core to cultivate. They will also never mention about taking someone's dantian out and cultivating with it, though it likely will be mentioned that it's possible for villainous/demonic practitioners to take Qi from other cultivators, usually through "nightly activities". There are a few exceptions, but not all that many, and even they aren't likely to overly give much explanation on what specifically the differences between having a dantian & a beast core is, mostly because it's usually irrelevant to the plot. Specifically in relation to Nine-tailed Foxes, how they are treated in Cultivation Novels varies. Sometime's they're animal-companions that may later develop a human form, sometime's they're humanoid from the get-go but have fox ears & tails (harem stories), and rarely are they some sort of wild beast, usually one that's treated like dragons are treated. That is to say, they're treated as if they are terrifying but intelligent, and may be willing to work on good terms with those who treat them with respect and dignity.
Generally, you're not going to see a single definition for a mythological creature unless we know the original story that said creature comes from. And even then, these stories are widely open to interpretation so there's nothing set in stone. Just look at the story of the Hydra: it comes from the Labors of Heracles, but its abilities evolved over time, so powers that we associate with it nowadays (like the regenerating heads) didn't exist at the beginning, and the key powers it originally had (like its venom) are largely forgotten now. The nine tail fox has been written about for a couple of thousand years, and its origins are lost to time so there's very little that we can say for sure about it. Broadly speaking, the most common interpretation is that it belongs to the group of animal spirits - animals that are either super old or have otherwise gained powers and wisdom to allow them to gain human attributes (or to outright transform into people). These creatures are super common in Chinese mythology and folklore so there are a million ways to interpret them. Modern writers will pick and choose whatever aspects they want from the old stories, and will often take ideas from non-mythological sources so you're never going to find something close to a consensus about this. So in general, just do whatever you want with the nine tail fox. If you're looking for inspiration, you can check out "the Investiture of the Gods" and "Journey to the West".