I have been killing "a fey uniter" and "a fey delerium" for about 12 hours. There is one uniter and 5 deleriums and I've kept them all dead. I have yet to see the "a fey swarm". The fey uniter always respawns as the uniter, but occasionally skips a spawn cycle. I suspect that the uniter is the PH for the named, and that the named pops and immediately despawns. Good luck getting that Hunter Achievement.
does this mob skip a spawn? does anythign kill it? after 3 hours 'farming' this pos mob and getting phs regularly, it did not spawn. I admit I am not a tracker, but there is only one path it takes that I saw. is the mob sos? do the hidden mobs attack it? does it go hang out in a bar somehwere and wait for me to leave the zone?
edit next spawn cycle, right on time, it showed up again. as if it died fast last time. but no one else is or was in the zone