That flat bitch got what she deserved for being a bitch. Instead of getting the big dick, she became a cumdump. Thats karma alright. Dunno about the dude at the end tho. Just cuz he doesnt appear doesnt mean he is dead, but feels weird.
Man this is why you don't draw without a storyboard. The plot isn't that hard to interpret but still a chore, but basically 1. The onsen water definitely laced with strong aphrodisiac (magical or otherwise), removing all sort of inhibition in people. 2. The Ryokan nympho is an immortal human, technically. However, her mother was the same until she got pregnant and become mortal again. So the Ryokan nympho will be the same, a normal human after becoming a bother.
What a fucking mess. Still NTR so if that's your cup of tea, definitely not mine.