In Episode 13, around 5:40 mark, we can see in action a demon that adopts the face of a man's wife. We see her returning to normal from a middle aged woman to a young woman who is also a bit better endowed (although the shots don't allow for much of that kind of process). At least the process is somehow smoothly animated... Sorry for the dissapointment
https://animeflv.net/ver/51749/dororo-13 full episode
https://drive.google.com/file/d/1pea...ew?usp=sharing TF clip (may have some display errors, check full episode better)