Talk:Nazarick Master Guarder/@comment-3245042-20180826211749/@comment-27033694-20180907172631

It means they are non customized NPCs. The POP NPCs under level 30 spawn without any expenses, while POP above level 30 and customized NPCs regardless their level spawn for gold.

Not only the Nazarick Guards but for example the Evil Lords, the Frost Virgins or the Overlords of the library are also POPs as far as I know. Or maybe they are the mercenary NPCs, I'm unsure.