Potentially Created by James Sutter
The creative director for Pathfinder James Jacobs has made several comments about Pharasma's naming over the years, mostly that she was renamed from his homebrew setting in the late 80s.
In my homebrew, Pharasma's name was Turthonir. I like Pharasma a thousand times better, and if/when I ever run something in my homebrew again, she's named Pharasma there too.
It was changed because Pharasma is such a more awesome name than Turhtonir.
He believed it was James Sutter that came up with the name "Pharasma" in another post on the Pathfinder forums.
In terms of inspiration for the deity, James Jacobs also gave a list of her biggest sources:
- Death, from Neil Gaiman's Sandman comics.
- Wee Jas, from Greyhawk.
- And a tiny drop of Kali