Where can I find them? Need someplace or instance where I can collect their defeats for badge. Paragonwiki has nothing on this NPC group.
Thanks.
Dev fail (I think they're trying to at this point). The enemy group is actually called Spirit Stalkers (http://paragonwiki.com/wiki/Spirit_Stalkers).
I added redirects to the wiki to point to the correct page for anyone looking for "Nightstalkers" or "Night Stalkers".
I was almost confused for a moment, because I took the screen-caps and grabbed the bio information myself one morning for that page... but then I realized the name.