Petersen has created a poster based on Mouse Guard: Fall 1152, the first story he created featuring his diminutive warriors.
“For the Fall 1152 poster I needed to re-create the events of that book in one image that summed everything up,” he wrote on his blog. “No problem, right? Harder than you think. I started with the idea that I should have the 3 main mouse characters as well as the snake (everyone still remembers that scene from the first issue). So, I sketched on copy paper, Lieam, Saxon and Kenzie with the plan to put Lieam front and center, with the other two either side of him. The snake would loom up over them from behind.”