Patch 1.05 will hit Diablo 3 tomorrow at 3AM PDT / 2AM BST according to an official post on Blizzard's forums . There will be an estimated ten hours of downtime while the patch is deployed, but once it's live we'll get access to the scalable Monster Power difficulty system, the high level Infernal Machine quest and dozens of class and item changes that Blizzard have been teasing for the past few months.
A new post on the Diablo 3 site drops details on the Infernal Machine quest that top level players can pursue to gain a unique Hellfire Ring. You'll find one of four new keywarden bosses patrolling each act. If you kill them with five Nephalem stacks on Inferno difficulty there's a chance they'll drop special keys and blacksmithing plans for the Infernal machine.
Once you have all the keys and the machine, you can open a portal that will randomly grant access to one of three chambers. Each is protected by a pair of bosses you'll recognise from the main campaign. Double teams include the Skeleton King and Magda, Ghom and Rakanoth and the Siege Breaker and Zoltan Kulle.
The infernal version of each boss will be more powerful than their campaign incarnation, and they'll have new moves to kill you with. Blizzard estimate that each boss is about as tough as Inferno Diablo.
Beating a boss pair will drop a ton of gold and loot but destroy the infernal machine. If you want a shot at a new boss pair, you'll have to craft the thing all over again. To get the Hellfire Ring, you have to beat every boss pair on five Nephalem stacks and hope that they drop organ pieces that your Jeweller can use to craft the ring.
The ring's properties are randomised, but you're guaranteed a +170-200 boost to strength, intelligence, dexterity or vitality (your choice) and a +35% experience boost designed to give future alts a quick leg up the levelling ranks.
That's not a bad item, but it sounds like it'll sure take a lot of work to get it.
The new monster power system improves drop rates, which will help Infernal Machine questers and anyone who fancies a challenge. It's detailed in full in this recent Blizzard blog post . Essentially, you can apply one of ten monster power boost levels to creatures in your playthrough, increasing their health and damage output, but nudging up rewards as well.
Check out our interview with Jay Wilson and Wyatt Cheng for the thinking behind tomorrow's monster patch.