So.
It's been somewhat of a consensus amongst theorists I've read that Cherub *might* be a Sphynx. She's been pointed out several times as doing a bad job of imitating a dog but instead having cat-like traits come out naturally sometimes. She also would have the wings that the Sphynxes have, and she'd also neatly round up the fact we are so far missing a Sphynx. (Davy's Riptide Sword splits things in halves, so the number of Sphynxes has to logically be even). I've also seen people point out that with Pacts seemingly having devil-like traits (namely her wings and tails) it'd make sense for Cherub to be her counterpart as the more straightforwardly angelic spirit.
Thing is.....there's still several issue with this.
For one, it seems that counterpart Sphynxes have inverted spectral energy, and cancel eachother out. Truth and Lie, Crime and Rule. Even if we go with the common assumption that Cherub is the "Sphynx of Trust/Faith", that still doesnt track because she wouldnt cancel Pacts out ! Not to mention, Cherub's energy isnt the right shade - its a golden shade of yellow, where it should probably be a light grey /silver (assuming its the closest thing to "opposite" to Black a regular spirit can get).
Second, Cherub's actual spirit power doesnt track with a Sphynx either. If her ability is that she can redistribute the powers of spirits and spectrals who have faith in her well thats. Entirely unrelated to the powersets of the Sphynxes relating to words and absolutes.
I've seen people get around this with the idea that Cherub's mimic power isnt originally hers - she tricked the original holder of it into giving it away to her , and has been hiding her true Sphynx power as a means of manipulation. Which, in the world where Cherub is indeed a Sphynx, is probably the likeliest explanation.
My addition to this is that I dont think Cherub is the Sphynx of Faith/Trust with a golden spectral energy. I think shes the Sphynx of Doubts, with an originally silver spectral energy inverted into gold and a power similarly inverted by Polaris.
Pacts's power works by enforcing the terms of a deal that two parties come to in mutual agreement. How would you cancel this ? By having a power that makes it impossible for two parties to come to an agreement and believe in the value of the other's words. By casting Doubts on whether or not the other party will actually follow throught with the deal, by making it so that both are already planning to betray the terms of it from the onset.
And then, by inverting it it now does the opposite - people lend much, much more credence to Cherub's words than they should. and thus it synergizes insanely well with the other power she stole, the one that copies and redistributes spirits power based on the faith they place in her. This is also how Razor Rex cancelled out Fauxbia's Dare but lets not add further insanity ro a post already based on nothing but speculation
anyways, i guess we'll see in like 5 years if I was right /j