Just keep in mind Cytherea is supposed to be the Big Bang, not a supernova. She’s supposed to be unknown not by choice but by nature. Like, her limitation should be the idea of the Planck time, the fact that we will never know what occurred at the exact instant of the beginning of existence. She’s also the Deist god (as opposed to Malfeas/Thein’s modern transcendent personal god). She sets things in motion and then forgets them. She doesn’t intervene except to create.
So she shouldn’t be a mustache-twirling villain, she should be unknowable by her very existence.
So instead of a bonus to remain hidden, she should have a forbiddance from using her Charms to make herself obvious.
Cytherea should be a creator, who does new things and makes lasting systems. She should be meticulous but not perfectionist. She does not care about the state of her creation beyond the moment of creation. She can apply her Excellency to any act to create a new thing; whether it be a object, artifact, social group, or a child. But she can not apply her Excellency to any attempts to repair or improve a thing once created.
As for her hiddenness, you should have:
Of Which Nothing Else Was Known
Cost: – Duration: Permanent Type: Permanent
Keywords: None
Mins: Essence 1
Cytherea is the mother of creation and none can know her beyond that. This Charm subtracts (Essence) successes from any attempt to locate the Infernal or uncover his handiwork in anything he does. It applies it to any evidence of his passing or his actions. This happens unconsciously and automatically. Even attempts to recall the Infernal’s actions after he ceases being present slowly fade, imposing the difficulty to rolls to recall his description or actions later.