Diablo 3's Patch 2.4.3 brings with it the "Darkening of Tristram" event, which re-creates the original Diablo cathedral dungeon.
Today, the special 20th Anniversary Patch for Diablo 3 went live, meaning you can now delve back into the original Diablo cathedral dungeon one more time.
The "Darkening of Tristram" event can be triggered by traveling to the "Darkening of Tristram" location in adventure mode, then traveling through the portal to teleport you to old Tristram. The game puts a super retro-filter on, which makes everything looked pixelated like the 1996 original game, and also alters a few UI elements to match. As you delve through the labyrinth, you'll battle classic enemies like The Butcher and Diablo himself, and be able to earn yourself some exclusive loot.
Most of the "new loot" is just cool trasmogs for your existing gear, with the only real new item being:
Red Soulstone Shard (Legendary Gem)
Periodically struggle for control, unleashing a ring of Fire that inflicts 12,500% weapon damage to enemies it passes through
After gaining a level, your resource costs are removed and cooldowns on skills are reduced by 75% for 30 seconds (Requires Rank 25)
The event only lasts until the end of January, so if you want to get your loot and achievements now is the time to boot Diablo 3 back up.