The Nighthawks were a group of warriors assigned to protect Nasuada from any dangers and attacks against her. The force consisted of thirty-four humans, dwarves and urgals, chosen not only for their strength, ability, as well as loyalty but also for their cunning intuition.
I see Jörmundur has surrounded me with warriors as skilled with their tongues as they are with their swords.— Lady Nasuada
The Nighthawks were assigned to Nasuada in rotations: six members at a time (presumably at least one of them a captain), two humans, two dwarves and two urgals, would accompany her continuously.
The Nighthawks relied more on reputation than displays of violence, to keep Nasuada safe. The idea was to make people believe that they were ‘the smartest, the toughest, and the meanest’ in order to ensure no one would dare to try and get past them.