I've read the 2kki wiki lately and I wonder just what makes people think that the twin mountains symbolize Urotsuki's twin? Actually, are there any more hints in the game that make us think so?
I don't get it, either. Maybe whoever came up with that theory also thought that the Urotsuki doppelgängers seen throughout game were an indication of her having a twin. I can't think of anything else at the moment.