Looters are generally harmless non-player characters that are found all around the Michigan, collecting scavenge and minding their own business. Larger groups can be encountered near the DMC and the Sprawl, enjoying the relative safety provided by the presence of the DMC Guards as well as possibility of trade that the Junk Market merchants give.
Looters generally pose a little threat, and have, initially, a neutral attitude towards the player's character. They are generally trying to avoid the fighting, agreeing to most of the proposals of ceasefire or negotiations, as well as retreating almost immediately when threatened.
Looters tend to try and steal items from the player's camp when he is not around or, sometimes, even when he is asleep.
As an unorganized group, looters don't have any real standing with any of the other factions. They are attacked on sight by members of the wilderness gangs, Bad Muthas and Blue Frogs. When meeting with DMC Guards, there is an equal chance for truce or violence.
There is no need to defend yourself against looters, though you may need to defend your items that are on the ground and not in your pack or hands. To easily scare off a looter, threaten them.
Rarely, some looters have been found with loaded guns. They have been known to shoot others with this emboldening weapon, so it is advised to be more careful around gun-wielding looters.
It's very hard to get close enough to a looter to hit them with a melee weapon. Thus, a gun is the preferred choice of weapon. Eagle eye, athletic, ranged, and tracking are useful for tracking down looters. Tracking aids you in following their trail, athletic helps you to keep up, eagle eye assists you in finding hiding looters, and ranged lets you shoot them with deadly accuracy.