NPCs (all npcs but guards) will not chase after you if you attack them, and NO npcs will run away when their health drops below a certain point (usually 10%)
NPC corpses are treated as blue corpses, but originally they were treated as if you killed a grey player that turned blue (you could loot them, but to everyone else they showed up as blue)
NPC corpses are treated as blue corpses, but originally they were treated as if you killed a grey player that turned blue (you could loot them, but to everyone else they showed up as blue)