If you attack an NPC loyal to a city or commune (like a guard) then all
on-line members of that city or commune will be treated as defenders of
that denizen. So they can kill you freely just as if they were to defend
a player you had declared hostilities against. This will make it easier
for you to defend your city/commune without the avenger interfering.

Penned by my hand on the 22nd of Dioni, in the year 132 CE.