*A doujinshi I like is Ultramadam as overall it's a parody on Ultraman gender swapped. It's R18, though more ryona and started to be about corruption as it went on. I suppose what I liked was the artwork; the attention to anatomy, poses is semi-realistic/realistic respectively. The linework seems simple while the coloring fills in the gaps at an almost minimal level unless an illustration. Nappi, the mangaka, seems to have stepped away and just posting on Ci-en now. I can only speculate burnout or something took away motivation from making doujin to now just sketch minis.
I've done two pieces of Ultramadam in the past and this time Mitsuko Minami. I'm planning on a fan set for her in Nappi's style (as above) and a few my way. I've a lot planned for these illustation sets, even for original work, so it's going to take awhile to get done between things. I've sketches for as many as came to mind, so WIPs will plentiful.