immortallity?? ah not realy haha , its justa spot that nobody cant attack u . monster can attack u there actualy but
pk or other nation cannot attack u at the spot ... its kinda usefull when u are grinding mutant plant and suddenly there other nation step in to farm honor from u ,just simply run to that spot and u will be safe from any harm
currently bug on aikasea ...never tested on other region
here the spot :
located at ungor forest near road of totem .
here the map
so if u guys testing it on other region , let me know the result