These are robot guards that patrol districts, but only certain streets. Usually all paved streets are patrol rooms and there is a chance that you see a guard there. The guarded areas are also the only ones where guards care about lewd conduct and where a guard appears if a characters takes a picture of lewd conduct in public.
Guards are appointed by the judge and the number of guards patrolling the district is fixed per day. If a guard is killed it is replaced by a new one. Each NPC guard must be paid once a day and the money for the guards is taken from the districts budged which in turn comes from taxes, so the citizens safety depends on tax pay. NPC guards also attack any NPC who is in a fight with a PC, so they help for example against morality fighter NPCs who attack PCs of opposite moral alignment but also when they see horde members fighting PCs.
When you fight against an NPC guard, you automatically receive 1 day prison term, regardless of why you are in a fight with the guard, so if a guard attacks you, try to run away, tale the beating but don't fight back unless you're already a criminal and one day prison term doesn't matter to you.
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