Northreach Wilds is a large northern PvP region, marked red on both maps. Use the map’s PvP region button to locate it. Inside, all combat levels can fight without receiving a new PK skull; normal death and dropped-backpack rules apply. Attacks across its boundary are blocked. Existing skulls remain. Outside this region, normal level protections apply. Protected areas prevent fighting. New-player and level-gap checks also restrict who can start a fight; the game explains a refused attack. An unjustified attack can give you a visible PK skull. Your status shows how long it remains.
Do not treat a town visit or a disconnect as a way to clear a skull. Check the current in-game warning before attacking another player. Use reporting for harassment and keep player trading separate from combat.