Light and shadow
Being unilluminated by light does not always make you difficult to see: Even the darkest shadow is unhelpful when your silhouette is on a backdrop of brilliant light. That said, a creature hidden in darkness against a dark wall should certainly get the concealment benefits of shadows.
Various items cast light out to different distances. Stacking light sources progresses like the cube root; 8 torches illuminate an area twice as wide as one. Bright illumination is followed by the same distance of dim illumination. Any surface that is brightly or dimly illuminated projects minimal illumination around it a great distance, 100 meters for dim and 500 for bright.
- Torches brightly illuminate out to 5 meters.
- Lightning very briefly brightly illuminates an area out to 18 meters.
- Sunlight brightly illuminates all it touches, and those things reflect enough light to brightly illuminate out to 10 meters.
- Moonlight dimly illuminates all it touches.