Archmage Arugal

Arugal's tower
Follow the upper passages through Fenrus's chamber, Nandos's kennel, and Arugal's room. Collect The Book of Ur before leaving Fenrus's shelves behind, and finish any Arugal's Voidwalkers before advancing. Clear the worgs around Nandos before pulling him. Clear the worgen in Arugal's room before starting the teleporting fight.
Archmage Arugal
Elite HumanoidArugal tests healing range across teleports while the group controls a player transformed by Arugal's Curse.
Abilities

Void Bolt
Keep Void Bolt's target in healing range when Arugal changes position; repeated Shadow hits can land while the group is moving.

Thundershock
Keep ranged players away from Arugal so Thundershock's nearby Nature damage and stun do not also stop their healing and attacks.

Arugal's Curse
Transforms an enemy into a Shadowfang Glutton, enslaving it to the caster's will for 10 seconds.
Control the charmed ally without killing them, then return to Arugal when the control ends.

Shadow Port
Re-establish range and line of sight after Shadow Port. Follow Arugal along the cleared route rather than chasing him through remaining worgen.
Tank- Reach Arugal again after Shadow Port without leaving healing range. Keep a charmed party member controlled rather than treating them as another enemy to kill.
Healer- Heal the current Void Bolt target from outside Thundershock's nearby area, and regain line of sight after each Shadow Port.
Damage- Move back into attack range after Shadow Port. Stop attacks on an ally changed by Arugal's Curse and use crowd control instead.