Wow weird. i was soloing outside the zone in and one of these popped (i conveniently just got an invite 3 secs after pop to a group) these guys actually aren't hard. they're not too fast and their HP are about as same as normal mobs. if i had not wasted half my mana on the mob it spawned from i could have soloed it. i got it to 25% on my own but had to mem blur it..... i then cast invis....here is the 2 things i want you to update about this mob. 1. i can confirm they do not see invis.... and 2. if it is spawned and not killed (someone mem blurs it or zones, a wipe w/e) it will stand there for oh maybe 2 minutes then cast Rift of Dranik's Scar (i know this cause i had joined the group and they had spell awareness...see there's a reason why i mentioned that hehe) it will then be surrounded by the same spell graphic the Priests of Discord get (the circle with a pic of Dranik's in the middle) and depop. I uploaded a pic of it porting as proof since i couldn't get a log on it in time :)
This mob will spawn when it's "host" (any mob in zone can be a "host") reaches about 50% HP. it will insta kill the mob (leaving the corpse to loot as seen in pic) and will say.
"An Unmasked Riftseeker draws the remaining life force from her host and redoubles her attack on <Insert target name here>" "An Unmasked Riftseeker says, You will not live to regret this"
it cons yellow to lvl 80 and does only drop 1 xp pot. same as found in the LoN cards. it seems to me she has been put in replacing the Unmasked Changelings that previously spawned here as old hotzone mobs :)