It is highly advised players use whatever incapacitating abilities they have on Dreadstalker, such as [Sap], [Hibernate], [Scare Beast], or any kind of fear abilities. Dreadstalker's poison debuff can be fatal. [Cleanse] and other similar abilities will also prove invaluable.
For those used to dealing with mobs that have pets, do not take down Dreadstalker first: Namkhare will resummon another.