The images in this series seem to be (but I am almost 100% sure) drawn by Akio Watanabe but colored by Fumio.
The way the hair twists, turns, and folds upon itself are clearly Watanabe. Likewise, the eyes and faces (incl. the recesses at the corners of the mouth and the drawn eyelids) are watanabe.
However, the coloring is purely Fumio, who uses multiple shades to color hair and uses smoothed/gradient shading on the body, whereas Watanabe uses 1 base color layer, 1 shade layer, 1 light layer and gradients only for things like blushes.