Both in the Tactical Map and the Operational Map, certain terrain grants a Hard DM to all ranged attacks. This is considered Natural Cover.
Natural Cover is not exclusive with Half Cover or Full Cover.

The following terrain features are considered Natural Cover:




The battlefield is considered dark when underground or when it is night-time and there are no sources of light nearby, such as streetlamps, lightbulbs or oil lamps.

All attacks gain a Very Hard DM to their hit rolls or skill checks.
Combat penalties for darkness are not exclusive with Natural Cover, Half Cover or Full Cover. Fighting in a dark forest is a terrible idea. Fighting an entrenched opponent equipped with Night Vision, in a jungle, during the night, is perhaps the worst idea imaginable.

Darkness can be negated in a number of ways: