Now as it stands, Legendary items are some of the top items in the game along with Set items. Well with patch 2.1.2, a new class of items called Ancients will be added. This is supposedly a class above Legendary which means that they’ll be a lot more desirable for gamers who will no doubt want to farm for it as much as they can.
So far from what is known about Ancients, they are basically upgraded versions of Legendary items where the Primary stats and secondary affixes will see a boost in numbers. They are exceedingly rare and can only be found on Torment difficulty games, with a 1.5% chance from a Legendary drop to be an Ancient drop, meaning that not only does your drop need to roll as a Legendary, but it needs to roll that it could be an Ancient as well.
The chance scales as you progress and goes up to 10% in Torment VI. No word on when patch 2.1.2 will be released, but it is playable on the PTR right now for gamers who are interested in learning about the changes.