the Sidhe tend to be more correct in their grammer of course, but that doesn't mean we don't have it wrong on our end, we just saw a 'she' or the vessel she used that let her manifest as Nemesis was itself female. If Beside comes into power through Justine I think what the general world will refer to 'it' as, would be vastly different than say if it's born into her male child. We already have an example of this, Drakul. He's clearly in a male body, but this in the know call him a creature and 'it'. 'It' all night be down to a certain prejudice of view. Despite becoming male, they still perceive him as the original unisex being. Mythology still perceives him as male though.
*Speculatively, perhaps Nemesis the Goddess is connected to one of the mantles still floating around and she's specifically trying to mirror it to become it's vessel?
** Old manifestations would still possess similar attributes of course. When Molly's use of fear was tempered to fall into grey areas of magic that didn't break free will, she suddenly resembled the winter lady enough to don the mantle. And the idea of such old manifestations being fed into the table of course, comes up with Mabs scales.
So tell me I'm understanding your current hypothesis:
- The Greek goddess Nemesis, daughter of Nyx and Erebus, was an Outsider all along. She got along well with native Insider gods and goddesses, had festivals and temples and a generally positive standing with the Greek populace.
- For some reason not said in mythology, Nemesis fell out of favor with humans and gods alike, and decided to become their enemy. She changed her nature from avatar of implacable justice to a shadowy spymaster that seeks to destroy all of reality and bring down everyone.
Is that what you're saying? Or am I misunderstanding?
EDIT: And to clarify, I'm just looking to confirm so I can approach theory crafting for it.
I.E. if you were saying Beside is Nemesis, then one might say Before is Oizys, and Behind is Moros.
Oizys, being one of Nemesis's sisters, who was the personification of misery/anxiety/depression, like we've seen Before's mental whammy cause. And Moros, being one of Nemesis's brothers, who was the personification of a mortal's impending doom, a hateful spirit that allowed mortals to foresee their death, much like how Behind taunted Harry.
All of which are children of Nyx (Night) and Erebus (Darkness), which, when combined, is basically Dark Night (presumably like a sky empty of stars).
There are other siblings, too, so there may be better fits, but those are the ones I found quickly.
EDIT 2:
Looking at the other siblings, I'd say Apate, the personification of deceit, would be a better fit for Beside than Nemesis.
Or Eris, goddess of stryfe and discord.
Or Dolos, Apate's male counterpart of deceit and treachery.
Or Hybris, goddess of insolence, violence, and outrageous behaviour.
The Moroi, the three weavers associated with the Mothers, were also siblings, being daughters of Nyx.