Hi Josh,
Love the concept and character. It looks like you have figured the lighting out somewhat subconsciously. The shaded part of the face and helmet (characters right side), has the potential to draw viewers eye to the glowing red eye. I think that emphasises that the light source can come from top left . This would allow the left arm, knife and even some of the devoured demon to be your point of interest. I'm no expert, but just sharing my thoughts. happy thoughts