The tier 2 eight-piece epic armor set drops primarily from bosses in Blackwing Lair. Early in the game, the set items dropped in Molten Core alongside Tier 1, but were removed in Patch 1.4. Tier 2 was readded in Patch 1.6 with the addition of Blackwing Lair. The tier 2 sets all had placeholder models, which were updated in Patch 1.9.
Due to frequent complaints of often looting "useless" druid or warlock gear, Blizzard implemented the "quest loot" concept for raids after Blackwing Lair (starting in Patch 1.7 with Zul'Gurub). With quest loot, bosses drop a token limited to three or four classes that would be turned in alongside other reagents and often also requires a high reputation standing with various factions. Quest loot was further refined in The Burning Crusade to the "loot token" concept, which did not require completing quests or turning in reagents.
Patch 1.4.0(2005-04-19): Prior to this patch, Molten Core boss creatures could drop items from one of two different tiered sets for every character class. The loot tables have been changed so Molten Core bosses will now only drop items from the lower tier class sets. However, some of the items from those sets were not previously dropping in Molten Core. These missing class set items will now drop in Molten Core, allowing players to complete their lower tier class sets. The higher tier class set pieces that once dropped in Molten Core will be found once again in Blackwing Lair, the next raiding zone scheduled for release in a future patch.