Tiviel, Tiefling from Reaper's Dark Heaven line (sculpted by Derek Schubert).
This was the first Tiefling I ever painted up, back in May of '11, and sold in June '11.
I converted her from the base sculpt quite a bit, which I'll go into detail here.
First I twisted her torso and legs a bit to give her a better contrappasto feel as I felt the original was too flat (which is a drawback to many one piece sculpts due to casting concerns unfortunately.)
I then repositioned both of her arms to have a more dynamic placement.
I gave her more hair to help fill the volume of her head out and balance the shapes.
I resculpted her mouth and a little of her face to give it more fullness. Very subtle changes.
Lastly I resculpted her abdomen and lower back to help the new anatomy to match the torso twist I gave her.
Blending her tail tip and base was done with oil paint and I used the same tone as her hair to help color balance. Sometimes I like to convert the default Reaper minis, but it's too time consuming so I rarely do it.