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.

Dungeon Journal
''Centuries ago, sorcerer-thane Thaurissan and seven of his most powerful Dark Iron allies accidentally summoned Ragnaros into Azeroth and damned their entire clan to enslavement. Although the Seven perished during the ritual, their restless spirits still linger in Blackrock Depths, cursed to serve their elemental master and the current Dark Iron ruler.''

Abilities
In alphabetic order (not the order you fight them), they are:

Vile'rel


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 appears and the door opens.

Notes and trivia

 * There was a legend about them, which was told in the "Tablet of the Seven".
 * Each name of The Seven is made of the name a bad feeling and the word "'rel".

Speculation

 * 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.