[Skills help] alertness

Automatic

Through alertness, a barbarian learns to be in-tune with his surroundings 
at all times, such that he can sense when someone is passing near his 
presence, even if they never make a sound.  Although dulled somewhat, a 
skilled barbarian can even sense people approach while he is sleeping.

This skill is the first step along a barbarian's path of supernatural
awareness that eventually leads to the ability to counterstrike.

See also: blind fighting, counterstrike