First of all - it's not REALLY a kuchisake-onna, but it's the more or less accurate way to call it, and besides it's hugely (hugely!!!) inspired by kuchisake-onna so.
This is Lei, naoli girl who was born to serve in one of the Naolus' temples. She was a vessel to a demon, which was a ritual matter, and at some point her demon was supposed to leave her - through her being put to death, naturally. Except she didn't die, and clung to her parasitic guest, slowly merging with it, instead of ever letting it go.
Naoli demons are all unique, there is no real classification in place, although sometimes they share some features. This particular one's method of being freed was slitting mouths of his vessels open - scar that Lei kept forever, although it only manifests itself when demon prevails over her own soul.
Anyway, small personal thing I drew over this evening. Idk. Sin just keeps saying I don't ever draw anything personal, so I'm trying to change it.