Rift Mob:Netharius  

Netharius, Droughtlands, Harlan's Lament

When he casts his shield is when he will cast the spell to summon adds. At some point he will bubble up (ward) and summon 1-3 Summoned Nethers. Use AE to kill them or switch target and dispatch them fast. His shield is also reflective so if you do not change targets you will only be hurting yourself.