progression...

Gruul's Lair
High King Maulgar
Gruul the Dragonkiller

Magtheridon's Lair
Magtheridon

Serpentshrine Cavern
Hydross the Unstable
The Lurker Below
Leotheras the Blind
Fathom-Lord Karathress
Morogrim Tidewalker
Lady Vashj

The Eye
A'lar the Phoenix God
Void Reaver
Astromancer Solarian
Kael'thas Sunstrider

Hyjal Summit
Rage Winterchill
Anetheron
Kazrogal
Azgalor
Archimonde

The Black Temple
High Warlord Najentus
Supremus
Shade of Akama
Teron Gorefiend
Gurtogg Bloodboil
Essence of Souls
Mother Shahraz
Illidari Council
Illidan Stormrage

Game over kids.