The Seven

The Seven were dark iron dwarves of great knowledge and power and the patriarchs of the Dark Iron nation. They were the dwarves who, along with Thaurissan, summoned Ragnaros the Firelord to Azeroth.

Though they died during the summoning and their people became enslaved by Ragnaros as a result, they seem to think that coming of the Firelord is a blessing.

In alphabetic order (not the order you fight them), they are:
 * Anger'rel: casts Strike (increases the caster's next melee attack), Shield Black, Sunder Armor
 * Doom'rel: casts Summon Voidwalkers (summons three Voidwalkers), Curse of Weakness, Demon Armor, Immolate, Shadowbolt Volley (targets everyone within 30 yards in front of the caster), leader of the Seven
 * Dope'rel: casts Sinister Strike, Backstab, Gouge
 * Gloom'rel: casts Cleave, Hamstring, Mortal Strike
 * Hate'rel: casts Strike, Shadowbolt, Mana Burn, Shadow Shield (shields a set amount of damage and deals shadow damage to melee attackers)
 * Seeth'rel:casts Blizzard, Frostbolt, Frost Nova, Frost Ward, Frost Armor
 * Vile'rel: casts Heal, Prayer of Healing, Power Word: Shield, Mind Blast

All of the mobs in the encounter are immune to curses. Also the event is entirely on a timer. After a set amount of seconds, the next mob will release and aggro the first player it sees.

Upon their defeat, the Chest of The Seven is appears and the door opens.

Trivia
Each name of The Seven is made of the name a bad feeling and the word "'rel".

Trivia

 * The Seven could be a reference to the seven dwarf-lords who received seven of the original twenty rings in J. R. R. Tolkien's The Lord of the Rings, though clearly the naming convention as mentioned above is similar to that used in the Disney version of Snow White and the Seven Dwarfs.