Blackwing Lair
Blackwing Lair can be found at the very height of Blackrock Spire and is a 40-man raid instance. It is there in the dark recesses of the mountain's peak that Nefarian has begun to unfold the final stages of his plan to destroy Ragnaros once and for all and lead his army to undisputed supremacy over all the races of Azeroth. To this end, he has recently begun efforts to bolster his forces, much as his father Deathwing had attempted to do in ages past.
All bosses in Blackwing Lair drop pieces of the Tier 2 Raid Set, excluding the leg, which drop from Ragnaros. Tier 2 helms used to drop from Onyxia, but now drop from Nefarian after Onyxia's revamp in 3.2.2.
Elementium Ingot is found as a rare drop from the Blackwing Technician that inhabit the lair. This ore is used to smelt 
Enchanted Elementium Bar, needed for 
Thunderfury, Blessed Blade of the Windseeker. Players can also learn 
Goblin's Guide to Elementium.
Many players will want to run Blackwing Lair for the distinctive weapons, including 
Claw of the Black Drake, 
Dragonbreath Hand Cannon, and 
Chromatically Tempered Sword.
