Drow assassin

The drow are an evil subrace of elves, living deep underground in the dangerous Underdark.

Special abilities
The darts of the drow assassin for levels 5 and above poison on-hit for d2 constitution damage with a DC of 14.

A drow assassin can cast darkness as a spell-like ability once per day with a caster level equal to his hit dice (to a maximum of 15).