Jane Snow? Hehe.
Alright, my nutty idea is this; I want to give an old idea of mine from way back another spin. If it doesn't fit the setting, I will cheerfully do something else though, because this concept as-is does imply things about cosmology.
short form is that the stars in the sky are quasi-divine entities set at the boundaries of creation, entrusted with the remnants of the primal energies originally used to make the universe. They have two functions. First, to safeguard the 'celestial fire' from those who would misuse it. Second, to use this empyreal flame to constantly reinforce and shore up the 'walls' of creation against the howling chaos of the Void beyond. The stars are wariors, ever faithful and set beyond the reach of man and god alike to fight for all time in the sky, alone except for one another.
All war is mostly waiting, and one past time to while away the eons is to gaze down at the tiny ball of rock and water entrusted to one of their number. And while many stars might have wished at one point or another to get closer, or to visit the tiny things they fought to shield, it was self-evident that such a thing could never happen.
Until one day, it did.
My character is not a star, of course. More like an avatar. A body created, imbued with tiny shred of life, mind and power that such a husk is capable of hosting, and sent hurtling like a meteor to the world. There to live among people, learning and experiencing, until it dies and that shard of essence returns to its source, letting the star partake of it. Her 'divine' powers are manifestations of the flame imperishable, which she wields through a focus that contains a sliver of it no greater than a grain of sand; plenty to power miracles on a mortal scale (her holy symbol equivalent).
As for how to tie her in, I have several ideas. Before I go into them though let me pause to hear from you. I would rather not invest a lot of time developing an idea that you decide isn't a good fit for the world. Once we have the story straight I can easily tie folks in.