This task is a pita to farm. You must trail Longshadow; if she gets out of range then you auto-fail and are booted from zone in 2 minutes. Once the task is completed, you still only have ~ 10 minutes before you're booted out anyway. Since the mobs in this instance do respawn, requesting the task once and then wrecking the place for the 6 hour task timer would be killer, but alas it ain't happenin!
Take a friend on this to farm it. Trail Longshadow killing the "ambushes" as he stops. Once you are at the last mob, "drachnid informant", do NOT kill it. Instead, off tank it without doing any damage. As one person off tanks the drachnid informant, the other person goes around killing mobs until the mask drops. Keep killing until everyone has there mask.
Found out why people where confused so decided to post info. Once you beat a mission on the normal setting it opens up the hard setting. You dont have to do all the previous missions on hard to get it.
BUT once you have WON this mission in order to see the hard setting you MUST ZONE then return. Thats all there is to it. Then when you request a mission from Shadowalker Dustspirit by telling him "hear the tale" and the window pops up all the hard missions will show for the missions you have already won on normal setting.
I realize the age of this post.. but you realize the "S" in KoS stands for sight right? If your camo as the lore describes, it can't SEE you. Thus not KoS. Its a perfectly reasonable question.