The SoulTaker
The SoulTaker is an anime series that focuses on Kyosuke Date who was killed by his mother, and afterward gained the ability to turn into a monster known as "The SoulTaker". The show was Tatsunoko's first attempt at a more adult series.
There is a spin-off OVA featuring Komugi, Nurse Witch Komugi. It is somewhat similar to Pretty Sammy, but shares more in common with Puni Puni Poemi.