A Dust, chasing after Jacob and the others. Illustrated by James Curwen.
(Read below for the illustration process if interested.)

Just to show readers what sort of process a typical illustrator goes through, I wanted to upload several sketches my cover designer, James Curwen, put together while we worked on a design we both liked.

Here, you can see the multiple versions of faces James created until I approved the one on the bottom right. (Which is why it has more detail than the others.)

Next, James started designing the body of the Dust, followed by the hands. He tried a lot of different hand options before settling on a torch.

Here, the Dust's hand is shaped like a knife. 

Here, like a rope.

And finally, we both really liked the Dust holding a torch. This is from when the Dust was chasing Jacob, Akeno, and the girl down the tunnel.

The above illustration has been inked - meaning, James took the pencil version and went over it with pen. It is now ready for him to shade, color, photoshop, trace to new paper, or do whatever else he wants to do with it.

He decided to trace to new paper and finish it with pencil, as you can see in the first illustration.