Board Thread:Dark Souls III/@comment-78.144.129.75-20160423154111/@comment-167.154.37.78-20160423164727

As far as I can tell they do only invade one time unlike number 2 where farming is an option. Not sure about NG+2 and beyond though. I can say however that I have had an NPC continually appear until I killed them but they weren't invaders (Havel and Hawkwood for instance)