Ruuzel

On my level 19 Druid, she was quite easy without any heirlooms or jewelry, I kept Moonfire for DoT and Rejuvenation for HoT up (both instant casts), and also Thorns for extra damage. If you cast Wrath just after a knock-back attack from her, it should be just enough time to cast it (2.5 sec cast time). She died in 30 seconds.

Any healing class should be fine imo:

If using the same strategy, Priests could use Shadow Word: Pain for DoT, Renew for HoT, and the occasional Holy Fire or Smite.

Shamans might want to wait until level 20 for this, since Healing Wave have 3 sec cast time, and at level 20 you get both Healing Surge (1.5 sec cast time) and Healing Stream Totem. Other than that, you could use Flame Shock and Searing Totem for DoT, and also shield, weapon imbue and other totem(s).

As for Paladins, Flash of Light (1.5 sec cast time) for heals, or if it works use Hammer of Justice and then Holy Light for a cheap heal if running low on mana. Crusader Strike and Judgement for damage, and also aura and seal.

To see the quest you must do the quest "The ancien statuettes". He give that quest.

When Ruuzel used her "death grip" ability that pulled my mage to her, it caused my character to fall through the ground and die in the "water" beneath the zone's geometry. That's a powerful attack!