Sometimes sketches work with the first go and other times they'll get worked out after a few passes and then get shelved in the end. In the upcoming Marquis and the Midwife, I had to design a "thug devil" for a later chapter in the book~ above are direct scans from my sketchbook showing everything on each page as I worked it out a couple years back. I never liked to sketch with pencil, so I just start scribbling out ideas straight with a pen to see what I come up with~ that way when something isn't going in the direction I want I'll just redraw it. Keep the bits I liked from the first go and add some new things with each drawing.
1) Was just playing with some shapes and ideas for a multi-jawed face. Stereotypical big lumbering shape, but weak design and not interesting to really look at. I liked the idea of the goat legs hanging from the rib cage and carried those over.
2) I always liked the idea of the devils in the Marquis having bits that matched the possessed human form, so the idea of a huge bicorn hat becoming the top of the devils head like a venus-flytrap stuck with me. The eyes were goofy looking though, so I got rid of them and made the devil blind. The body shape still matched a lot of what I had sketched earlier.
3 and 4) I worked up details to the design from the previous page~ the devil had to feel like a fighter, so I figured it would have big club like arms and the goat legs in the mid-section would kick out in a fight. With a final design for the body I liked, I added some marker greys to flesh it out.
5) I still liked the idea of it being blind, but instead of having a barren face I decided to make the face pitted with holes like a rotted nasal cavity in a skull.
But in the end, I didn't like the feel of it for the character I had planned and reworked the entire idea into something stronger. But this "thug devil" might get another pass and show up in a different Marquis book down the line.