Technically the Hanged Man hangs by his foot upside down, but the nature of hanging around the neck is more simple to convey visually (and doesn't require contrivement), so my interest is always piqued when characters get hanged. (Normal thing to say on Tumblr).
That's the scene for my being in the middle of torturing myself thinking about Jonas as the Hanged Man, who gets hanged twice, once through an aborted execution and once as a suicide attempt - poor Jonas -
then remembered that Cinder's got her neck scar just like his, which is not from a hanging, but a collar.
I actually first thought of the Girl with the Green Ribbon when I saw it, where if the girl takes off the ribbon securing her neck, she'll die. I view this scene where Cinder takes the collar off (which is symbolically confluent with the Grimm curse - this is the collar/leash to her master) as a type of symbolic death, when she is made "dead" stuck at midnight - whatever this release could've been, it's instead the background for her intiation into Salem's cult. This is not happy.
The Grimm arm itself is her most clear chthonic theming, but I think what's important is that narratively we have a consistent thread of collar -> Grimm bug -> Grimm arm for every time Cinder appears onscreen - her torture at Salem's feet, mimicking that of her previous master from the collar/arm, is fairly on the nose in this regard.
Cinder's in a state of death (or essentially undeath), and is most importantly the story's introduction to death and the death of innocence. Notably the hybridity with the Grimm puts her in a vampiric state where she consumes Aura through the arm - an arm unprotected by Aura itself, covetous of something it can't really have or even protect herself with.
What I think is most symbolically important for her (on this front) is that the vampiric force will never be successful in securing the Maiden power - it only merits her half of the Fall Maiden power to begin with, leaving her unwhole - until she retrieves it more rightly and justly with Midnight, for all that it can be right and just (at least in the face of what they're about to do to Pyrrha, which I view as categorically wrong).
I laid out her overall chthonic background here again and how this contributes to her permanent state of literal unrest and alienation, because it symbolically ties to what the Hanged Man is (seeming death) but like all things in R/WBY this amuses me because in the brokenness is the promise of wholeness (see also: "the wound that can be healed only by the weapon that dealt it").
I took a bit of a gander but tarot is a bit more heterogenous than what I'm used to with this material, but Wikipedia sources this and it seems to be a fairly legitimate (particularly for the sort of thing one finds influencing R/WBY) so I went to find the full extract of the text where a very meaningful part is left out (the lattermost bolding) - from The Pictorial Key to Tarot, originally published in 1911, A. E. Waite, also the source for the tarot card above:
There is a nimbus about the head of the seeming martyr. It should be noted
1. that the tree of sacrifice is living wood, with leaves thereon;
2. that the face expresses deep entrancement, not suffering;
3. that the figure, as a whole, suggests life in suspension, but life and not death.
It is a card of profound significance, but all the significance is veiled.
[...]
It has been called falsely a card of martyrdom, a card of prudence, a card of the Great Work, a card of duty; but we may exhaust all published interpretations and find only vanity.
I will say very simply on my own part that it expresses the relation, in one of its aspects, between the Divine and the Universe.
He who can understand that the story of his higher nature is imbedded in this symbolism will receive intimations concerning a great awakening that is possible, and will know that after the sacred Mystery of Death there is a glorious Mystery of Resurrection.
Emphasis mine. The "life in suspension" portion is interesting to me because this pretty much 1:1 describes Cinder's unrest. I also thought it was so cutely Cinder that "the significance is veiled." Key to victory baby! If Ruby's silver eyes are the key to Cinder being freed from the curse (easy to say, hard to do), then that Mystery of Death holds in it the lesson that is the Mystery of Resurrection. It's all very monomythic as well - the passage to the underworld, to the knowledge of death denied to the living, brings with it sacred and secret knowledge, and the elixir of life.
If Ruby's eyes protect life, Cinder's curse - symbolically, literally - is death and saps the waters of life (Aura), then the two of them, with each other integrated, Shadow and White Shadow, are resurrection.
The thing that interests me about anything related to what Cinder becomes in this story - dead and dealt with, Fall Maiden power alotted to a better, more deserving recipient - I just can't help but think, how do you kill a person who's already dead? It's the same problem with Salem - she can't be killed because she's the Queen of the Grimm (dead), and spiritually, she is annihilated.
It's hard to say how far any tarot influence extends - I've toyed with this in the past with Beacon Tower and Salem's, as points of electric and dramatic transformation in the story, and reading this book now I suspect even something like the Magician and the High Priestess have something to do with Ozlem - though if there is a presence at all feels more questionable than something more concrete, in my view, like the Jung or the Campbell, particularly on this note given that the Hanged Man comes at a bit of a stretch. But it already highlights what I think to be true (endless midnight/curse/chthonic theming), so it's complementary as opposed to revelational. What's more is that the neck scar directly is veiled and meaningfully revealed, tied to her backstory that's been hidden - it's meant to be a reverse of Adam (I think) where his story has been used to wrangle others, specifically Blake, into submission, whereas Cinder's story has been used to wrangle her into submission beneath Salem - and so its imagery feels pretty potent already. It's the secret of her undeath, life in suspension, and the question of whether she will answer the lesson of the Fall Maiden or not. For the matter of resurrection, it's also about redemption.
To return back to Jonas, of course, and the mystery of Dark, it's his hanging scar which is an identifying feature throughout his lives lived out in the story - it's how his future self proves himself to him, and it's the mark of intense agony, and the wrongness that he feels that he is, for his whole life, spent on the warped world. But in a moment of transcendence - for originally what he thought would destroy everything, instead a nanosecond of opportunity for change opens up; after his death, he is resurrected. I can post this .gif because I literally made it myself, as I needed the moment of resurrection and mutual recognition (with Martha, who loves him, and is a bit like the Mary Magdalene here) as my cover photo:
This is where you can really see the sunlight motif coalesce - this is the day the original world (the cosmic egg) splits in two on the day of the summer solstice (yes, they paid that much attention; I checked), and the day that Jonas is symbolically resurrected. Previously, in a world of intense darkness, the sunlight coated scenes of naïveté yet contrastingly the (often mystic) sex scenes - these were kind of contradictory, because Jonas and Martha are the wrongness and the wound, but you've got positive (opposite) imagery to the show's literal name - Dark - paired with the thing that's supposed to be bad before and after a time of innocence. Instead I realised that the sunlight, used very sparingly, represents this forbidden relationship, that the love potion and the poison are the same potion (per Campbell again), and that death is resurrection, and Jonas-Martha is the weapon to heal the wound. It's only through this method that they eventually... well!
Both of these are stories which go deep into Jung and the monomyth with vastly divergent tone and medium, but it's kind of fun to tie them together this way. I think it's clear that whether Dark dips into tarot, the monomythic ideas of death and resurrection are present, and similar ones you can certainly see playing out in R/WBY... maybe extending to a certain Fall Maiden, even embodied in her season - the dying of things, and the fruitful harvest.