I've never heard of this demon and will be looking up more about the history of this. My assumption would be that it's miscarriage related based on the specifics of the attacks, but the separating in half is such a unique thing to be a part of demon lore that I'm curious to know more. Probably long lost to time but very interesting.
Also I like how you kill it:
Sprinkling salt, smearing crushed garlic or ash on top of the standing torso is fatal to the creature. The upper torso then would not be able to rejoin itself and would perish by sunrise.