These creatures are highly dedicated spellcasters and can prove frustrating to melee warriors with their use of Clumsiness and especially Sympathetic Visage. No one is safe from Wastrel's Worry, and one would be well advised to bring at least one fast-activation skill to avoid the damage it causes. It is dangerous to have one person attack Reed Stalkers while the rest of the party remains outside their spellcasting range: Clumsiness and Wastrel's Worry will decimate them. Generally speaking, it is safest for everyone to remain inside aggro range so as to even out the distribution of Wastrel's Worry.
Reed Stalkers deal Chaos damage, and while it does not ignore armor, there are no specific armor types or skills that protect against it.